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Chapter 1.2: Transformation Kinetics
Chapter 1: Radioactivity Chapter 1.2: Transformation Kinetics 200 NPRE 441, Principles of Radiation Protection Chapter 1: Radioactivity http://www.world‐nuclear.org/info/inf30.html 201 NPRE 441, Principles of Radiation Protection Chapter 1: Radioactivity Serial Transformation In many situations, the parent nuclides produce one or more radioactive offsprings in a chain. In such cases, it is important to consider the radioactivity from both the parent and the daughter nuclides as a function of time. • Due to their short half lives, 90Kr and 90Rb will be completely transformed, results in a rapid building up of 90Sr. • 90Y has a much shorter half‐life compared to 90Sr. After a certain period of time, the instantaneous amount of 90Sr transformed per unit time will be equal to that of 90Y. •Inthiscase,90Y is said to be in a secular equilibrium. 202 NPRE 441, Principles of Radiation Protection Chapter 1: Radioactivity Exponential DecayTransformation Kinetics • Different isotopes are characterized by their different rate of transformation (decay). • The activity of a pure radionuclide decreases exponentially with time. For a given sample, the number of decays within a unit time window around a given time t is a Poisson random variable, whose expectation is given by t Q Q0e •Thedecayconstant is the probability of a nucleus of the isotope undergoing a decay within a unit period of time. 203 NPRE 441, Principles of Radiation Protection Chapter 1: Radioactivity Why Exponential Decay? The decay rate, A, is given by Separate variables in above equation, we have The decay constant is the probability of a nucleus of the isotope undergoing a decay within a unit period of time. -
R-Process Elements from Magnetorotational Hypernovae
r-Process elements from magnetorotational hypernovae D. Yong1,2*, C. Kobayashi3,2, G. S. Da Costa1,2, M. S. Bessell1, A. Chiti4, A. Frebel4, K. Lind5, A. D. Mackey1,2, T. Nordlander1,2, M. Asplund6, A. R. Casey7,2, A. F. Marino8, S. J. Murphy9,1 & B. P. Schmidt1 1Research School of Astronomy & Astrophysics, Australian National University, Canberra, ACT 2611, Australia 2ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D), Australia 3Centre for Astrophysics Research, Department of Physics, Astronomy and Mathematics, University of Hertfordshire, Hatfield, AL10 9AB, UK 4Department of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA 5Department of Astronomy, Stockholm University, AlbaNova University Center, 106 91 Stockholm, Sweden 6Max Planck Institute for Astrophysics, Karl-Schwarzschild-Str. 1, D-85741 Garching, Germany 7School of Physics and Astronomy, Monash University, VIC 3800, Australia 8Istituto NaZionale di Astrofisica - Osservatorio Astronomico di Arcetri, Largo Enrico Fermi, 5, 50125, Firenze, Italy 9School of Science, The University of New South Wales, Canberra, ACT 2600, Australia Neutron-star mergers were recently confirmed as sites of rapid-neutron-capture (r-process) nucleosynthesis1–3. However, in Galactic chemical evolution models, neutron-star mergers alone cannot reproduce the observed element abundance patterns of extremely metal-poor stars, which indicates the existence of other sites of r-process nucleosynthesis4–6. These sites may be investigated by studying the element abundance patterns of chemically primitive stars in the halo of the Milky Way, because these objects retain the nucleosynthetic signatures of the earliest generation of stars7–13. -
Harry Moseley: Numbering the Elements
MYSTERY OF MATTER: SEARCH FOR THE ELEMENTS 5. Harry Moseley: Numbering the Elements Dmitri Mendeleev (identified on screen) works on the Periodic Table, writes down the atomic weights of the elements. NARR: Previously on The Mystery of Matter… HISTORIAN MICHAEL GORDIN VO He figures out something rather extraordinary about the elements. DMITRI MENDELEEV, partly in VO The eye is immediately struck by a pattern within the horizontal rows and the vertical columns. Mendeleev’s first table morphs into the familiar modern Periodic Table. AUTHOR ERIC SCERRI VO He found an absolutely fundamental principle of nature. Humphry Davy (identified on screen) performs an experiment with his voltaic pile. HISTORIAN DAVID KNIGHT VO Somehow the particles of matter have to be glued together to form molecules. What Davy has had is a big idea. Perhaps electricity could be this kind of glue. Marie Curie (identified on screen) sits down at the spectroscope and peers into the eyepiece. NARR: The spectroscope kicked off a whole new round in the discovery of elements. The spectra of four elements appear on screen, along with their names. PHYSICIST DAVID KAISER VO It’s almost like each element has its own bar code. Marie and Pierre enter their lab at night and see vials of radium glowing on the shelves. MARIE TO PIERRE Don’t light the lamps! Look! 1 MYSTERY OF MATTER: SEARCH FOR THE ELEMENTS PHYSICIST DAVID KAISER VO Radioactivity was a sign that the atom itself was unstable. It could break apart. Marie and Pierre look in wonder at their radiant element. NARR: Scientists now had a pressing new question to answer: What’s inside the atom? Fade to black ANNOUNCER: Major funding for The Mystery of Matter: Search for the Elements was provided by the National Science Foundation, where discoveries begin. -
Experimental Γ Ray Spectroscopy and Investigations of Environmental Radioactivity
Experimental γ Ray Spectroscopy and Investigations of Environmental Radioactivity BY RANDOLPH S. PETERSON 216 α Po 84 10.64h. 212 Pb 1- 415 82 0- 239 β- 01- 0 60.6m 212 1+ 1630 Bi 2+ 1513 83 α β- 2+ 787 304ns 0+ 0 212 α Po 84 Experimental γ Ray Spectroscopy and Investigations of Environmental Radioactivity Randolph S. Peterson Physics Department The University of the South Sewanee, Tennessee Published by Spectrum Techniques All Rights Reserved Copyright 1996 TABLE OF CONTENTS Page Introduction ....................................................................................................................4 Basic Gamma Spectroscopy 1. Energy Calibration ................................................................................................... 7 2. Gamma Spectra from Common Commercial Sources ........................................ 10 3. Detector Energy Resolution .................................................................................. 12 Interaction of Radiation with Matter 4. Compton Scattering............................................................................................... 14 5. Pair Production and Annihilation ........................................................................ 17 6. Absorption of Gammas by Materials ..................................................................... 19 7. X Rays ..................................................................................................................... 21 Radioactive Decay 8. Multichannel Scaling and Half-life ..................................................................... -
Models of the Atomic Nucleus
Models of the Atomic Nucleus Second Edition Norman D. Cook Models of the Atomic Nucleus Unification Through a Lattice of Nucleons Second Edition 123 Prof. Norman D. Cook Kansai University Dept. Informatics 569 Takatsuki, Osaka Japan [email protected] Additional material to this book can be downloaded from http://extras.springer.com. ISBN 978-3-642-14736-4 e-ISBN 978-3-642-14737-1 DOI 10.1007/978-3-642-14737-1 Springer Heidelberg Dordrecht London New York Library of Congress Control Number: 2010936431 © Springer-Verlag Berlin Heidelberg 2006, 2010 This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilm or in any other way, and storage in data banks. Duplication of this publication or parts thereof is permitted only under the provisions of the German Copyright Law of September 9, 1965, in its current version, and permission for use must always be obtained from Springer. Violations are liable to prosecution under the German Copyright Law. The use of general descriptive names, registered names, trademarks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. Cover design: WMXDesign GmbH, Heidelberg Printed on acid-free paper Springer is part of Springer Science+Business Media (www.springer.com) Preface to the Second Edition Already by the 1970s, some theorists had declared that nuclear structure physics was a “closed chapter” in science, but since then it has repeatedly been found necessary to re-open this closed chapter to address old problems and to explain new phenom- ena. -
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. -
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. -
The Use of Gamma in Place of Digamma in Ancient Greek
Mnemosyne (2020) 1-22 brill.com/mnem The Use of Gamma in Place of Digamma in Ancient Greek Francesco Camagni University of Manchester, UK [email protected] Received August 2019 | Accepted March 2020 Abstract Originally, Ancient Greek employed the letter digamma ( ϝ) to represent the /w/ sound. Over time, this sound disappeared, alongside the digamma that denoted it. However, to transcribe those archaic, dialectal, or foreign words that still retained this sound, lexicographers employed other letters, whose sound was close enough to /w/. Among these, there is the letter gamma (γ), attested mostly but not only in the Lexicon of Hesychius. Given what we know about the sound of gamma, it is difficult to explain this use. The most straightforward hypothesis suggests that the scribes who copied these words misread the capital digamma (Ϝ) as gamma (Γ). Presenting new and old evidence of gamma used to denote digamma in Ancient Greek literary and documen- tary papyri, lexicography, and medieval manuscripts, this paper refutes this hypoth- esis, and demonstrates that a peculiar evolution in the pronunciation of gamma in Post-Classical Greek triggered a systematic use of this letter to denote the sound once represented by the digamma. Keywords Ancient Greek language – gamma – digamma – Greek phonetics – Hesychius – lexicography © Francesco Camagni, 2020 | doi:10.1163/1568525X-bja10018 This is an open access article distributed under the terms of the CC BY 4.0Downloaded license. from Brill.com09/30/2021 01:54:17PM via free access 2 Camagni 1 Introduction It is well known that many ancient Greek dialects preserved the /w/ sound into the historical period, contrary to Attic-Ionic and Koine Greek. -
3 Gamma-Ray Detectors
3 Gamma-Ray Detectors Hastings A Smith,Jr., and Marcia Lucas S.1 INTRODUCTION In order for a gamma ray to be detected, it must interact with matteu that interaction must be recorded. Fortunately, the electromagnetic nature of gamma-ray photons allows them to interact strongly with the charged electrons in the atoms of all matter. The key process by which a gamma ray is detected is ionization, where it gives up part or all of its energy to an electron. The ionized electrons collide with other atoms and liberate many more electrons. The liberated charge is collected, either directly (as with a proportional counter or a solid-state semiconductor detector) or indirectly (as with a scintillation detector), in order to register the presence of the gamma ray and measure its energy. The final result is an electrical pulse whose voltage is proportional to the energy deposited in the detecting medhtm. In this chapter, we will present some general information on types of’ gamma-ray detectors that are used in nondestructive assay (NDA) of nuclear materials. The elec- tronic instrumentation associated with gamma-ray detection is discussed in Chapter 4. More in-depth treatments of the design and operation of gamma-ray detectors can be found in Refs. 1 and 2. 3.2 TYPES OF DETECTORS Many different detectors have been used to register the gamma ray and its eneqgy. In NDA, it is usually necessary to measure not only the amount of radiation emanating from a sample but also its energy spectrum. Thus, the detectors of most use in NDA applications are those whose signal outputs are proportional to the energy deposited by the gamma ray in the sensitive volume of the detector. -
Radiation and Radioactivity Quantified? Do You Think of These “People” When I Say RADIATION? Do You Think of These Things As Well?
Welcome To RadTown USA •Click to Explore RadTown USA • Click on any location in RadTown USA and find out about radiation sources or uses at that location. The Alpha, Beta, Gammas of Nuclear Education March 2nd, 2014 Fundamentals of Ionizing Radiation Debra N Thrall, PhD Executive Director Albert I Pierce Foundation Radiation Fundamentals What is radiation? Where does it come from? How does it interact with matter? What is radioactivity? What are fission and fusion? How are radiation and radioactivity quantified? Do you think of these “people” when I say RADIATION? Do you think of these things as well? • Food • Space • Utilities • Consumer Products • Medicine Brief History of the Atom • 500 BC Democritus Atom • Long time (Romans Dark Ages) • 1808 AD Dalton Plum Pudding • 1911 Rutherford Nucleus • 1913 Bohr Orbits • 1920’s Many People Quantum Mechanics Rutherford’s Gold Foil Experiment The Design 1. Bombard positively charged alpha particles into thin gold foil. 2. Use fluorescent screen to detect particles as they exit the gold foil. 3. Use angle of deflection to determine interior of the atom. So, What is an Atom? • Atoms are made up of protons, neutrons & electrons • Protons: + charge p+ • Neutrons: no charge n0 • Electrons: - charge e- • Atoms want to have a stable energy level • This translates to having no net charge • # protons = # electrons Mass of an Atom • Masses • Proton: 1.000000 amu • Neutron: 1.000000 amu • Electron: 0.000549 amu (Translates to 1.2 lbs/1 ton ~ a kitten on an elephant!) • The mass of an atom is approximately -
How Do Radioactive Materials Move Through the Environment to People?
5. How Do Radioactive Materials Move Through the Environment to People? aturally occurring radioactive materials Radionuclides can be removed from the air in Nare present in our environment and in several ways. Particles settle out of the our bodies. We are, therefore, continuously atmosphere if air currents cannot keep them exposed to radiation from radioactive atoms suspended. Rain or snow can also remove (radionuclides). Radionuclides released to them. the environment as a result of human When these particles are removed from the activities add to that exposure. atmosphere, they may land in water, on soil, or Radiation is energy emitted when a on the surfaces of living and non-living things. radionuclide decays. It can affect living tissue The particles may return to the atmosphere by only when the energy is absorbed in that resuspension, which occurs when wind or tissue. Radionuclides can be hazardous to some other natural or human activity living tissue when they are inside an organism generates clouds of dust containing radionu- where radiation released can be immediately clides. absorbed. They may also be hazardous when they are outside of the organism but close ➤ Water enough for some radiation to be absorbed by Radionuclides can come into contact with the tissue. water in several ways. They may be deposited Radionuclides move through the environ- from the air (as described above). They may ment and into the body through many also be released to the water from the ground different pathways. Understanding these through erosion, seepage, or human activities pathways makes it possible to take actions to such as mining or release of radioactive block or avoid exposure to radiation. -
Radioactive Decay
North Berwick High School Department of Physics Higher Physics Unit 2 Particles and Waves Section 3 Fission and Fusion Section 3 Fission and Fusion Note Making Make a dictionary with the meanings of any new words. Einstein and nuclear energy 1. Write down Einstein’s famous equation along with units. 2. Explain the importance of this equation and its relevance to nuclear power. A basic model of the atom 1. Copy the components of the atom diagram and state the meanings of A and Z. 2. Copy the table on page 5 and state the difference between elements and isotopes. Radioactive decay 1. Explain what is meant by radioactive decay and copy the summary table for the three types of nuclear radiation. 2. Describe an alpha particle, including the reason for its short range and copy the panel showing Plutonium decay. 3. Describe a beta particle, including its range and copy the panel showing Tritium decay. 4. Describe a gamma ray, including its range. Fission: spontaneous decay and nuclear bombardment 1. Describe the differences between the two methods of decay and copy the equation on page 10. Nuclear fission and E = mc2 1. Explain what is meant by the terms ‘mass difference’ and ‘chain reaction’. 2. Copy the example showing the energy released during a fission reaction. 3. Briefly describe controlled fission in a nuclear reactor. Nuclear fusion: energy of the future? 1. Explain why nuclear fusion might be a preferred source of energy in the future. 2. Describe some of the difficulties associated with maintaining a controlled fusion reaction.