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The R-Process Nucleosynthesis and Related Challenges
EPJ Web of Conferences 165, 01025 (2017) DOI: 10.1051/epjconf/201716501025 NPA8 2017 The r-process nucleosynthesis and related challenges Stephane Goriely1,, Andreas Bauswein2, Hans-Thomas Janka3, Oliver Just4, and Else Pllumbi3 1Institut d’Astronomie et d’Astrophysique, Université Libre de Bruxelles, CP 226, 1050 Brussels, Belgium 2Heidelberger Institut fr¨ Theoretische Studien, Schloss-Wolfsbrunnenweg 35, 69118 Heidelberg, Germany 3Max-Planck-Institut für Astrophysik, Postfach 1317, 85741 Garching, Germany 4Astrophysical Big Bang Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan Abstract. The rapid neutron-capture process, or r-process, is known to be of fundamental importance for explaining the origin of approximately half of the A > 60 stable nuclei observed in nature. Recently, special attention has been paid to neutron star (NS) mergers following the confirmation by hydrodynamic simulations that a non-negligible amount of matter can be ejected and by nucleosynthesis calculations combined with the predicted astrophysical event rate that such a site can account for the majority of r-material in our Galaxy. We show here that the combined contribution of both the dynamical (prompt) ejecta expelled during binary NS or NS-black hole (BH) mergers and the neutrino and viscously driven outflows generated during the post-merger remnant evolution of relic BH-torus systems can lead to the production of r-process elements from mass number A > 90 up to actinides. The corresponding abundance distribution is found to reproduce the∼ solar distribution extremely well. It can also account for the elemental distributions observed in low-metallicity stars. However, major uncertainties still affect our under- standing of the composition of the ejected matter. -
Chapter 3 the Fundamentals of Nuclear Physics Outline Natural
Outline Chapter 3 The Fundamentals of Nuclear • Terms: activity, half life, average life • Nuclear disintegration schemes Physics • Parent-daughter relationships Radiation Dosimetry I • Activation of isotopes Text: H.E Johns and J.R. Cunningham, The physics of radiology, 4th ed. http://www.utoledo.edu/med/depts/radther Natural radioactivity Activity • Activity – number of disintegrations per unit time; • Particles inside a nucleus are in constant motion; directly proportional to the number of atoms can escape if acquire enough energy present • Most lighter atoms with Z<82 (lead) have at least N Average one stable isotope t / ta A N N0e lifetime • All atoms with Z > 82 are radioactive and t disintegrate until a stable isotope is formed ta= 1.44 th • Artificial radioactivity: nucleus can be made A N e0.693t / th A 2t / th unstable upon bombardment with neutrons, high 0 0 Half-life energy protons, etc. • Units: Bq = 1/s, Ci=3.7x 1010 Bq Activity Activity Emitted radiation 1 Example 1 Example 1A • A prostate implant has a half-life of 17 days. • A prostate implant has a half-life of 17 days. If the What percent of the dose is delivered in the first initial dose rate is 10cGy/h, what is the total dose day? N N delivered? t /th t 2 or e Dtotal D0tavg N0 N0 A. 0.5 A. 9 0.693t 0.693t B. 2 t /th 1/17 t 2 2 0.96 B. 29 D D e th dt D h e th C. 4 total 0 0 0.693 0.693t /th 0.6931/17 C. -
Photofission Cross Sections of 238U and 235U from 5.0 Mev to 8.0 Mev Robert Andrew Anderl Iowa State University
Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations 1972 Photofission cross sections of 238U and 235U from 5.0 MeV to 8.0 MeV Robert Andrew Anderl Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/rtd Part of the Nuclear Commons, and the Oil, Gas, and Energy Commons Recommended Citation Anderl, Robert Andrew, "Photofission cross sections of 238U and 235U from 5.0 MeV to 8.0 MeV " (1972). Retrospective Theses and Dissertations. 4715. https://lib.dr.iastate.edu/rtd/4715 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. INFORMATION TO USERS This dissertation was produced from a microfilm copy of the original document. While the most advanced technological means to photograph and reproduce this document have been used, the quality is heavily dependent upon the quality of the original submitted. The following explanation of techniques is provided to help you understand markings or patterns which may appear on this reproduction, 1. The sign or "target" for pages apparently lacking from the document photographed is "Missing Page(s)". If it was possible to obtain the missing page(s) or section, they are spliced into the film along with adjacent pages. This may have necessitated cutting thru an image and duplicating adjacent pages to insure you complete continuity, 2. -
Electron Capture in Stars
Electron capture in stars K Langanke1;2, G Mart´ınez-Pinedo1;2;3 and R.G.T. Zegers4;5;6 1GSI Helmholtzzentrum f¨urSchwerionenforschung, D-64291 Darmstadt, Germany 2Institut f¨urKernphysik (Theoriezentrum), Department of Physics, Technische Universit¨atDarmstadt, D-64298 Darmstadt, Germany 3Helmholtz Forschungsakademie Hessen f¨urFAIR, GSI Helmholtzzentrum f¨ur Schwerionenforschung, D-64291 Darmstadt, Germany 4 National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA 5 Joint Institute for Nuclear Astrophysics: Center for the Evolution of the Elements, Michigan State University, East Lansing, Michigan 48824, USA 6 Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA E-mail: [email protected], [email protected], [email protected] Abstract. Electron captures on nuclei play an essential role for the dynamics of several astrophysical objects, including core-collapse and thermonuclear supernovae, the crust of accreting neutron stars in binary systems and the final core evolution of intermediate mass stars. In these astrophysical objects, the capture occurs at finite temperatures and at densities at which the electrons form a degenerate relativistic electron gas. The capture rates can be derived in perturbation theory where allowed nuclear transitions (Gamow-Teller transitions) dominate, except at the higher temperatures achieved in core-collapse supernovae where also forbidden transitions contribute significantly to the rates. There has been decisive progress in recent years in measuring Gamow-Teller (GT) strength distributions using novel experimental techniques based on charge-exchange reactions. These measurements provide not only data for the GT distributions of ground states for many relevant nuclei, but also serve as valuable constraints for nuclear models which are needed to derive the capture rates for the arXiv:2009.01750v1 [nucl-th] 3 Sep 2020 many nuclei, for which no data exist yet. -
2.3 Neutrino-Less Double Electron Capture - Potential Tool to Determine the Majorana Neutrino Mass by Z.Sujkowski, S Wycech
DEPARTMENT OF NUCLEAR SPECTROSCOPY AND TECHNIQUE 39 The above conservatively large systematic hypothesis. TIle quoted uncertainties will be soon uncertainty reflects the fact that we did not finish reduced as our analysis progresses. evaluating the corrections fully in the current analysis We are simultaneously recording a large set of at the time of this writing, a situation that will soon radiative decay events for the processes t e'v y change. This result is to be compared with 1he and pi-+eN v y. The former will be used to extract previous most accurate measurement of McFarlane the ratio FA/Fv of the axial and vector form factors, a et al. (Phys. Rev. D 1984): quantity of great and longstanding interest to low BR = (1.026 ± 0.039)'1 I 0 energy effective QCD theory. Both processes are as well as with the Standard Model (SM) furthermore very sensitive to non- (V-A) admixtures in prediction (Particle Data Group - PDG 2000): the electroweak lagLangian, and thus can reveal BR = (I 038 - 1.041 )*1 0-s (90%C.L.) information on physics beyond the SM. We are currently analyzing these data and expect results soon. (1.005 - 1.008)* 1W') - excl. rad. corr. Tale 1 We see that even working result strongly confirms Current P1IBETA event sxpelilnentstatistics, compared with the the validity of the radiative corrections. Another world data set. interesting comparison is with the prediction based on Decay PIBETA World data set the most accurate evaluation of the CKM matrix n >60k 1.77k element V d based on the CVC hypothesis and ihce >60 1.77_ _ _ results -
Nuclear Equations
Nuclear Equations In nuclear equations, we balance nucleons (protons and neutrons). The atomic number (number of protons) and the mass number (number of nucleons) are conserved during the reaction. Nuclear Equations Alpha Decay Nuclear Equations Beta Decay Nuclear Equations Beta Decay Nuclear Equations Positron Emission: A positron is a particle equal in mass to an electron but with opposite charge. Nuclear Equations Electron Capture: A nucleus absorbs an electron from the inner shell. Nuclear Equations EXAMPLE 4.1 Balancing Nuclear Equations Write balanced nuclear equations for each of the following processes. In each case, indicate what new element is formed. a. Plutonium-239 emits an alpha particle when it decays. b. Protactinium-234 undergoes beta decay. c. Carbon-11 emits a positron when it decays. d. Carbon-11 undergoes electron capture. EXAMPLE 4.1 Balancing Nuclear Equations continued Exercise 4.1 Write balanced nuclear equations for each of the following processes. In each case, indicate what new element is formed. a. Radium-226 decays by alpha emission. b. Sodium-24 undergoes beta decay. c. Gold-188 decays by positron emission. d. Argon-37 undergoes electron capture. EXAMPLE 4.2 More Nuclear Equations 5 In the upper atmosphere, a nitrogen-14 nucleus absorbs a neutron. A carbon-14 nucleus and another particle are formed. What is the other particle? Half-Life Half-life of a radioactive sample is the time required for ½ of the material to undergo radioactive decay. Half-Life Half-Life Fraction Remaining = 1/2n Half-life T1/2 = 0.693/ k(decay constant) If you know how much you started with and how much you ended with, then you can determine the number of half-lives. -
Theory of Nuclear Excitation by Electron Capture for Heavy Ions
Theory of nuclear excitation by electron capture for heavy ions Inaugural Dissertation zur Erlangung des Doktorgrades der Naturwissenschaften der Justus-Liebig-Universit¨at Gießen Fachbereich 07 vorgelegt von Adriana Gagyi-P´alffy aus Bukarest, Rum¨anien Gießen 2006 Dekan: Prof. Dr. Volker Metag 1. Berichterstatter: Prof. Dr. Werner Scheid 2. Berichterstatter: Prof. Dr. Alfred Muller¨ Tag der mundlic¨ hen Prufung:¨ Contents Introduction 5 Aim and motivation of this thesis . 6 Contents of this thesis . 7 1 Theory of electron recombination 9 1.1 Decomposition of the Fock space . 11 1.2 The total Hamiltonian of the system . 12 1.3 Expansion of the transition operator . 14 1.4 Total cross section for NEEC . 18 2 Theory of NEEC 21 2.1 Nuclear model . 21 2.2 NEEC rates for electric transitions . 27 2.3 NEEC rates for magnetic transitions . 29 3 Total cross sections for NEEC 31 3.1 Numerical results . 31 3.2 Possible experimental observation of NEEC . 37 3.2.1 Electron Beam Ion Traps . 37 3.2.2 Ion Accelerators . 40 4 Interference between NEEC and RR 45 4.1 Interference term in the total cross section . 45 4.2 Electric transitions . 50 4.3 Magnetic transitions . 52 4.4 Numerical results . 54 5 Angular distribution of emitted radiation 59 5.1 Alignment of the excited nuclear state . 60 5.2 Radiative decay of the excited nuclear state . 62 5.3 Numerical results . 65 Summary and Outlook 73 Summary . 73 Outlook . 74 Deutschsprachige Zusammenfassung 77 3 CONTENTS Appendix A The magnetic Hamiltonian 81 B Magnetic transitions in the nuclear collective model 85 C Calculation of matrix elements involving spherical tensors 89 Bibliography 95 Acknowledgments 107 4 Introduction When Niels Bohr proposed in 1913 his first model of the atom, he depicted it as having a small and dense positively charged nucleus, surrounded by the orbiting electrons. -
Photofission Cross Sections of 232Th and 236U from Threshold to 8
Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations 1972 Photofission cross sections of 232Th nda 236U from threshold to 8 MeV Michael Vincent Yester Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/rtd Part of the Nuclear Commons Recommended Citation Yester, Michael Vincent, "Photofission cross sections of 232Th nda 236U from threshold to 8 MeV " (1972). Retrospective Theses and Dissertations. 6137. https://lib.dr.iastate.edu/rtd/6137 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. INFORMATION TO USERS This dissertation was produced from a microfilm copy of the original document. While the most advanced technological means to photograph and reproduce this document have been used, the quality is heavily dependent upon the quality of the original submitted. The following explanation of techniques is provided to help you understand markings or patterns which may appear on this reproduction. 1. The sign or "target" for pages apparently lacking from the document photographed is "Missing Page(s)". If it was possible to obtain the missing page(s) or section, they are spliced into the film along with adjacent pages. This may have necessitated cutting thru an image and duplicating adjacent pages to insure you complete continuity. 2. When an image on the film is obliterated with a large round black mark, it is an indication that the photographer suspected that the copy may have moved during exposure and thus cause a blurred image. -
Introduction to Nuclear Physics and Nuclear Decay
NM Basic Sci.Intro.Nucl.Phys. 06/09/2011 Introduction to Nuclear Physics and Nuclear Decay Larry MacDonald [email protected] Nuclear Medicine Basic Science Lectures September 6, 2011 Atoms Nucleus: ~10-14 m diameter ~1017 kg/m3 Electron clouds: ~10-10 m diameter (= size of atom) water molecule: ~10-10 m diameter ~103 kg/m3 Nucleons (protons and neutrons) are ~10,000 times smaller than the atom, and ~1800 times more massive than electrons. (electron size < 10-22 m (only an upper limit can be estimated)) Nuclear and atomic units of length 10-15 = femtometer (fm) 10-10 = angstrom (Å) Molecules mostly empty space ~ one trillionth of volume occupied by mass Water Hecht, Physics, 1994 (wikipedia) [email protected] 2 [email protected] 1 NM Basic Sci.Intro.Nucl.Phys. 06/09/2011 Mass and Energy Units and Mass-Energy Equivalence Mass atomic mass unit, u (or amu): mass of 12C ≡ 12.0000 u = 19.9265 x 10-27 kg Energy Electron volt, eV ≡ kinetic energy attained by an electron accelerated through 1.0 volt 1 eV ≡ (1.6 x10-19 Coulomb)*(1.0 volt) = 1.6 x10-19 J 2 E = mc c = 3 x 108 m/s speed of light -27 2 mass of proton, mp = 1.6724x10 kg = 1.007276 u = 938.3 MeV/c -27 2 mass of neutron, mn = 1.6747x10 kg = 1.008655 u = 939.6 MeV/c -31 2 mass of electron, me = 9.108x10 kg = 0.000548 u = 0.511 MeV/c [email protected] 3 Elements Named for their number of protons X = element symbol Z (atomic number) = number of protons in nucleus N = number of neutrons in nucleus A A A A (atomic mass number) = Z + N Z X N Z X X [A is different than, but approximately equal to the atomic weight of an atom in amu] Examples; oxygen, lead A Electrically neural atom, Z X N has Z electrons in its 16 208 atomic orbit. -
Double-Beta Decay of 96Zr and Double-Electron Capture of 156Dy to Excited Final States
Double-Beta Decay of 96Zr and Double-Electron Capture of 156Dy to Excited Final States by Sean W. Finch Department of Physics Duke University Date: Approved: Werner Tornow, Supervisor Calvin Howell Kate Scholberg Berndt Mueller Albert Chang Dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Physics in the Graduate School of Duke University 2015 Abstract Double-Beta Decay of 96Zr and Double-Electron Capture of 156Dy to Excited Final States by Sean W. Finch Department of Physics Duke University Date: Approved: Werner Tornow, Supervisor Calvin Howell Kate Scholberg Berndt Mueller Albert Chang An abstract of a dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Physics in the Graduate School of Duke University 2015 Copyright c 2015 by Sean W. Finch All rights reserved except the rights granted by the Creative Commons Attribution-Noncommercial License Abstract Two separate experimental searches for second-order weak nuclear decays to excited final states were conducted. Both experiments were carried out at the Kimballton Underground Research Facility to provide shielding from cosmic rays. The first search is for the 2νββ decay of 96Zr to excited final states of the daughter nucleus, 96Mo. As a byproduct of this experiment, the β decay of 96Zr was also investigated. Two coaxial high-purity germanium detectors were used in coincidence to detect γ rays produced by the daughter nucleus as it de-excited to the ground state. After collecting 1.92 years of data with 17.91 g of enriched 96Zr, half-life limits at the level of 1020 yr were produced. -
Nuclear Chemistry Why? Nuclear Chemistry Is the Subdiscipline of Chemistry That Is Concerned with Changes in the Nucleus of Elements
Nuclear Chemistry Why? Nuclear chemistry is the subdiscipline of chemistry that is concerned with changes in the nucleus of elements. These changes are the source of radioactivity and nuclear power. Since radioactivity is associated with nuclear power generation, the concomitant disposal of radioactive waste, and some medical procedures, everyone should have a fundamental understanding of radioactivity and nuclear transformations in order to evaluate and discuss these issues intelligently and objectively. Learning Objectives λ Identify how the concentration of radioactive material changes with time. λ Determine nuclear binding energies and the amount of energy released in a nuclear reaction. Success Criteria λ Determine the amount of radioactive material remaining after some period of time. λ Correctly use the relationship between energy and mass to calculate nuclear binding energies and the energy released in nuclear reactions. Resources Chemistry Matter and Change pp. 804-834 Chemistry the Central Science p 831-859 Prerequisites atoms and isotopes New Concepts nuclide, nucleon, radioactivity, α− β− γ−radiation, nuclear reaction equation, daughter nucleus, electron capture, positron, fission, fusion, rate of decay, decay constant, half-life, carbon-14 dating, nuclear binding energy Radioactivity Nucleons two subatomic particles that reside in the nucleus known as protons and neutrons Isotopes Differ in number of neutrons only. They are distinguished by their mass numbers. 233 92U Is Uranium with an atomic mass of 233 and atomic number of 92. The number of neutrons is found by subtraction of the two numbers nuclide applies to a nucleus with a specified number of protons and neutrons. Nuclei that are radioactive are radionuclides and the atoms containing these nuclei are radioisotopes. -
Chapter 16 Nuclear Chemistry
Chapter 16 275 Chapter 16 Nuclear Chemistry Review Skills 16.1 The Nucleus and Radioactivity Nuclear Stability Types of Radioactive Emissions Nuclear Reactions and Nuclear Equations Rates of Radioactive Decay Radioactive Decay Series The Effect of Radiation on the Body 16.2 Uses of Radioactive Substances Medical Uses Carbon-14 Dating Other Uses for Radioactive Nuclides 16.3 Nuclear Energy Nuclear Fission and Electric Power Plants Nuclear Fusion and the Sun Special Topic 16.1: A New Treatment for Brain Cancer Special Topic 16.2: The Origin of the Elements Chapter Glossary Internet: Glossary Quiz Chapter Objectives Review Questions Key Ideas Chapter Problems 276 Study Guide for An Introduction to Chemistry Section Goals and Introductions Section 16.1 The Nucleus and Radioactivity Goals To introduce the new terms nucleon, nucleon number, and nuclide. To show the symbolism used to represent nuclides. To explain why some nuclei are stable and others not. To provide you with a way of predicting nuclear stability. To describe the different types of radioactive decay. To show how nuclear reactions are different from chemical reactions. To show how nuclear equations are different from chemical equations. To show how the rates of radioactive decay can be described with half-life. To explain why short-lived radioactive atoms are in nature. To describe how radiation affects our bodies.. This section provides the basic information that you need to understand radioactive decay. It will also help you understand the many uses of radioactive atoms, including how they are used in medicine and in electricity generation. Section 16.2 Uses of Radioactive Substances Goal: To describe many of the uses of radioactive atoms, including medical uses, archaeological dating, smoke detectors, and food irradiation.