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Hetc-3Step Calculations of Proton Induced Nuclide Production Cross Sections at Incident Energies Between 20 Mev and 5 Gev
JAERI-Research 96-040 JAERI-Research—96-040 JP9609132 JP9609132 HETC-3STEP CALCULATIONS OF PROTON INDUCED NUCLIDE PRODUCTION CROSS SECTIONS AT INCIDENT ENERGIES BETWEEN 20 MEV AND 5 GEV August 1996 Hiroshi TAKADA, Nobuaki YOSHIZAWA* and Kenji ISHIBASHI* Japan Atomic Energy Research Institute 2 G 1 0 1 (T319-11 l This report is issued irregularly. Inquiries about availability of the reports should be addressed to Research Information Division, Department of Intellectual Resources, Japan Atomic Energy Research Institute, Tokai-mura, Naka-gun, Ibaraki-ken, 319-11, Japan. © Japan Atomic Energy Research Institute, 1996 JAERI-Research 96-040 HETC-3STEP Calculations of Proton Induced Nuclide Production Cross Sections at Incident Energies between 20 MeV and 5 GeV Hiroshi TAKADA, Nobuaki YOSHIZAWA* and Kenji ISHIBASHP* Department of Reactor Engineering Tokai Research Establishment Japan Atomic Energy Research Institute Tokai-mura, Naka-gun, Ibaraki-ken (Received July 1, 1996) For the OECD/NEA code intercomparison, nuclide production cross sections of l60, 27A1, nalFe, 59Co, natZr and 197Au for the proton incidence with energies of 20 MeV to 5 GeV are calculated with the HETC-3STEP code based on the intranuclear cascade evaporation model including the preequilibrium and high energy fission processes. In the code, the level density parameter derived by Ignatyuk, the atomic mass table of Audi and Wapstra and the mass formula derived by Tachibana et al. are newly employed in the evaporation calculation part. The calculated results are compared with the experimental ones. It is confirmed that HETC-3STEP reproduces the production of the nuclides having the mass number close to that of the target nucleus with an accuracy of a factor of two to three at incident proton energies above 100 MeV for natZr and 197Au. -
An Octad for Darmstadtium and Excitement for Copernicium
SYNOPSIS An Octad for Darmstadtium and Excitement for Copernicium The discovery that copernicium can decay into a new isotope of darmstadtium and the observation of a previously unseen excited state of copernicium provide clues to the location of the “island of stability.” By Katherine Wright holy grail of nuclear physics is to understand the stability uncover its position. of the periodic table’s heaviest elements. The problem Ais, these elements only exist in the lab and are hard to The team made their discoveries while studying the decay of make. In an experiment at the GSI Helmholtz Center for Heavy isotopes of flerovium, which they created by hitting a plutonium Ion Research in Germany, researchers have now observed a target with calcium ions. In their experiments, flerovium-288 previously unseen isotope of the heavy element darmstadtium (Z = 114, N = 174) decayed first into copernicium-284 and measured the decay of an excited state of an isotope of (Z = 112, N = 172) and then into darmstadtium-280 (Z = 110, another heavy element, copernicium [1]. The results could N = 170), a previously unseen isotope. They also measured an provide “anchor points” for theories that predict the stability of excited state of copernicium-282, another isotope of these heavy elements, says Anton Såmark-Roth, of Lund copernicium. Copernicium-282 is interesting because it University in Sweden, who helped conduct the experiments. contains an even number of protons and neutrons, and researchers had not previously measured an excited state of a A nuclide’s stability depends on how many protons (Z) and superheavy even-even nucleus, Såmark-Roth says. -
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. -
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. -
Compilation and Evaluation of Fission Yield Nuclear Data Iaea, Vienna, 2000 Iaea-Tecdoc-1168 Issn 1011–4289
IAEA-TECDOC-1168 Compilation and evaluation of fission yield nuclear data Final report of a co-ordinated research project 1991–1996 December 2000 The originating Section of this publication in the IAEA was: Nuclear Data Section International Atomic Energy Agency Wagramer Strasse 5 P.O. Box 100 A-1400 Vienna, Austria COMPILATION AND EVALUATION OF FISSION YIELD NUCLEAR DATA IAEA, VIENNA, 2000 IAEA-TECDOC-1168 ISSN 1011–4289 © IAEA, 2000 Printed by the IAEA in Austria December 2000 FOREWORD Fission product yields are required at several stages of the nuclear fuel cycle and are therefore included in all large international data files for reactor calculations and related applications. Such files are maintained and disseminated by the Nuclear Data Section of the IAEA as a member of an international data centres network. Users of these data are from the fields of reactor design and operation, waste management and nuclear materials safeguards, all of which are essential parts of the IAEA programme. In the 1980s, the number of measured fission yields increased so drastically that the manpower available for evaluating them to meet specific user needs was insufficient. To cope with this task, it was concluded in several meetings on fission product nuclear data, some of them convened by the IAEA, that international co-operation was required, and an IAEA co-ordinated research project (CRP) was recommended. This recommendation was endorsed by the International Nuclear Data Committee, an advisory body for the nuclear data programme of the IAEA. As a consequence, the CRP on the Compilation and Evaluation of Fission Yield Nuclear Data was initiated in 1991, after its scope, objectives and tasks had been defined by a preparatory meeting. -
1 Lecture Notes in Nuclear Structure Physics B. Alex Brown November
1 Lecture Notes in Nuclear Structure Physics B. Alex Brown November 2005 National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy Michigan State University, E. Lansing, MI 48824 CONTENTS 2 Contents 1 Nuclear masses 6 1.1 Masses and binding energies . 6 1.2 Q valuesandseparationenergies . 10 1.3 Theliquid-dropmodel .......................... 18 2 Rms charge radii 25 3 Charge densities and form factors 31 4 Overview of nuclear decays 40 4.1 Decaywidthsandlifetimes. 41 4.2 Alphaandclusterdecay ......................... 42 4.3 Betadecay................................. 51 4.3.1 BetadecayQvalues ....................... 52 4.3.2 Allowedbetadecay ........................ 53 4.3.3 Phase-space for allowed beta decay . 57 4.3.4 Weak-interaction coupling constants . 59 4.3.5 Doublebetadecay ........................ 59 4.4 Gammadecay............................... 61 4.4.1 Reduced transition probabilities for gamma decay . .... 62 4.4.2 Weisskopf units for gamma decay . 65 5 The Fermi gas model 68 6 Overview of the nuclear shell model 71 7 The one-body potential 77 7.1 Generalproperties ............................ 77 7.2 Theharmonic-oscillatorpotential . ... 79 7.3 Separation of intrinsic and center-of-mass motion . ....... 81 7.3.1 Thekineticenergy ........................ 81 7.3.2 Theharmonic-oscillator . 83 8 The Woods-Saxon potential 87 8.1 Generalform ............................... 87 8.2 Computer program for the Woods-Saxon potential . .... 91 8.2.1 Exampleforboundstates . 92 8.2.2 Changingthepotentialparameters . 93 8.2.3 Widthofanunboundstateresonance . 94 8.2.4 Width of an unbound state resonance at a fixed energy . 95 9 The general many-body problem for fermions 97 CONTENTS 3 10 Conserved quantum numbers 101 10.1 Angularmomentum. 101 10.2Parity .................................. -
Heavy Element Nucleosynthesis
Heavy Element Nucleosynthesis A summary of the nucleosynthesis of light elements is as follows 4He Hydrogen burning 3He Incomplete PP chain (H burning) 2H, Li, Be, B Non-thermal processes (spallation) 14N, 13C, 15N, 17O CNO processing 12C, 16O Helium burning 18O, 22Ne α captures on 14N (He burning) 20Ne, Na, Mg, Al, 28Si Partly from carbon burning Mg, Al, Si, P, S Partly from oxygen burning Ar, Ca, Ti, Cr, Fe, Ni Partly from silicon burning Isotopes heavier than iron (as well as some intermediate weight iso- topes) are made through neutron captures. Recall that the prob- ability for a non-resonant reaction contained two components: an exponential reflective of the quantum tunneling needed to overcome electrostatic repulsion, and an inverse energy dependence arising from the de Broglie wavelength of the particles. For neutron cap- tures, there is no electrostatic repulsion, and, in complex nuclei, virtually all particle encounters involve resonances. As a result, neutron capture cross-sections are large, and are very nearly inde- pendent of energy. To appreciate how heavy elements can be built up, we must first consider the lifetime of an isotope against neutron capture. If the cross-section for neutron capture is independent of energy, then the lifetime of the species will be ( )1=2 1 1 1 µn τn = ≈ = Nnhσvi NnhσivT Nnhσi 2kT For a typical neutron cross-section of hσi ∼ 10−25 cm2 and a tem- 8 9 perature of 5 × 10 K, τn ∼ 10 =Nn years. Next consider the stability of a neutron rich isotope. If the ratio of of neutrons to protons in an atomic nucleus becomes too large, the nucleus becomes unstable to beta-decay, and a neutron is changed into a proton via − (Z; A+1) −! (Z+1;A+1) + e +ν ¯e (27:1) The timescale for this decay is typically on the order of hours, or ∼ 10−3 years (with a factor of ∼ 103 scatter). -
A Guide to Naturally Occurring Radioactive Materials (NORM)
ABOUT NORM SOME NORM NUCLIDES OF SPECIAL INTEREST A Guide to Naturally There are three types of NORM: Occurring Radioactive • Cosmogenic – NORM produced by cosmic rays interacting with the Earth’s Materials (NORM) Beryllium 7 atmosphere; the most important Developed by the 3 7 14 examples are H (tritium), Be, and C. 7Be is being continuously formed in the DHS Secondary Reachback Program • Primordial – Sufficiently long-lived atmosphere by cosmic rays. Jet engines can March 2010 NORM for some to have survived from accumulate enough 7Be to set off before the formation of the Earth; there radiological alarms when being cleaned. are 20 primordial NORM nuclides with As defined by the International Atomic the most important being 40K, 232Th, Energy Agency (IAEA), Naturally 235U, and 238U. Polonium 210 Occurring Radioactive Materials • Daughters – When 232Th, 235U and 238U In the 238U decay chain 210Po is a distant (NORM) include all natural radioactive decay 42 different radioactive nuclides daughter of 226Ra. 210Po gained notoriety in materials where human activities have are formed (see below) with the most the 1960s as a radioactive trace component increased the potential for exposure in important being 222Rn, 226Ra, 228Ra and in cigarette smoke. Heavy use of phosphate comparison with the unaltered natural 228 Ac. fertilizers (which have trace amounts of out here. fold Next situation. If processing has increased 226Ra) can triple the amount of 210Po found the concentrations of radionuclides in a When 232Th, 235U and 238U decay a in tobacco. material then it is Technologically radioactive “daughter” nuclide is formed, Enhanced NORM (TE-NORM). -
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. -
Mass Defect & Binding Energy
Sem-3 CC7 Nuclear Physics Mass Defect & Binding Energy According to nuclear particle experiments, the total mass of a nucleus (mnuc) is less than the sum of the masses of its constituent nucleons (protons and neutrons). For a nucleus with Z protons and mass number A, the mass difference or mass defect is given by Δm= Zmp + (A−Z)mn − mnuc where Zmp is the total mass of the protons, (A−Z)mn is the total mass of the neutrons, and mnuc is the mass of the nucleus. According to Einstein’s special theory of relativity, mass is a measure of the total energy of a system (E=mc2). The energy equivalent to mass defect is alled the binding energy B of the nucleus. Thus 2 B= [Zmp + (A−Z)mn − mnuc] c The binding energy is equal to the amount of energy released in forming the nucleus. Example 1. Calculate the mass defect and the binding energy of the deuteron. The mass of the −27 deuteron is mD=3.34359×10 kg or 2.014102u. Solution For the deuteron Z=1 and A=2. The mass defect for the deuteron is Δm=mp+mn−mD=1.008665 u+ 1.007825 u- 2.014102u = 0.002388u The binding energy of the deuteron is then B= Δm c2= Δm ×931.5 MeV/u=2.224MeV. Over two million electron volts are needed to break apart a deuteron into a proton and a neutron. This very large value indicates the great strength of the nuclear force. By comparison, the greatest amount of energy required to liberate an electron bound to a hydrogen atom by an attractive Coulomb force (an electromagnetic force) is about 10 eV. -
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. -
The Discoverers of the Ruthenium Isotopes
•Platinum Metals Rev., 2011, 55, (4), 251–262• The Discoverers of the Ruthenium Isotopes Updated information on the discoveries of the six platinum group metals to 2010 http://dx.doi.org/10.1595/147106711X592448 http://www.platinummetalsreview.com/ By John W. Arblaster This review looks at the discovery and the discoverers Wombourne, West Midlands, UK of the thirty-eight known ruthenium isotopes with mass numbers from 87 to 124 found between 1931 and 2010. Email: [email protected] This is the sixth and fi nal review on the circumstances surrounding the discoveries of the isotopes of the six platinum group elements. The fi rst review on platinum isotopes was published in this Journal in October 2000 (1), the second on iridium isotopes in October 2003 (2), the third on osmium isotopes in October 2004 (3), the fourth on palladium isotopes in April 2006 (4) and the fi fth on rhodium isotopes in April 2011 (5). An update on the new isotopes of palladium, osmium, iridium and platinum discovered since the previous reviews in this series is also included. Naturally Occurring Ruthenium Of the thirty-eight known isotopes of ruthenium, seven occur naturally with the authorised isotopic abun- dances (6) shown in Table I. The isotopes were fi rst detected in 1931 by Aston (7, 8) using a mass spectrograph at the Cavendish Laboratory, Cambridge University, UK. Because of diffi cult experimental conditions due to the use of poor quality samples, Aston actually only detected six of the isotopes and obtained very approximate Table I The Naturally Occurring Isotopes of Ruthenium Mass number Isotopic Abundance, % 96Ru 5.54 98Ru 1.87 99Ru 12.76 100Ru 12.60 101Ru 17.06 102Ru 31.55 104Ru 18.62 251 © 2011 Johnson Matthey http://dx.doi.org/10.1595/147106711X592448 •Platinum Metals Rev., 2011, 55, (4)• percentage abundances.