DATABASE of PROMPT GAMMA RAYS from SLOW NEUTRON CAPTURE for ELEMENTAL ANALYSIS the Following States Are Members of the International Atomic Energy Agency

Total Page:16

File Type:pdf, Size:1020Kb

DATABASE of PROMPT GAMMA RAYS from SLOW NEUTRON CAPTURE for ELEMENTAL ANALYSIS the Following States Are Members of the International Atomic Energy Agency $ATABASEOF0ROMPT'AMMA2AYS FROM3LOW.EUTRON#APTUREFOR %LEMENTAL!NALYSIS DATABASE OF PROMPT GAMMA RAYS FROM SLOW NEUTRON CAPTURE FOR ELEMENTAL ANALYSIS The following States are Members of the International Atomic Energy Agency: AFGHANISTAN GREECE NORWAY ALBANIA GUATEMALA PAKISTAN ALGERIA HAITI PANAMA ANGOLA HOLY SEE PARAGUAY ARGENTINA HONDURAS PERU ARMENIA HUNGARY PHILIPPINES AUSTRALIA ICELAND POLAND AUSTRIA INDIA PORTUGAL AZERBAIJAN INDONESIA QATAR BANGLADESH IRAN, ISLAMIC REPUBLIC OF REPUBLIC OF MOLDOVA BELARUS IRAQ ROMANIA BELGIUM IRELAND RUSSIAN FEDERATION BELIZE ISRAEL SAUDI ARABIA BENIN ITALY SENEGAL BOLIVIA JAMAICA SERBIA BOSNIA AND HERZEGOVINA JAPAN SEYCHELLES BOTSWANA JORDAN SIERRA LEONE BRAZIL KAZAKHSTAN SINGAPORE BULGARIA KENYA SLOVAKIA BURKINA FASO KOREA, REPUBLIC OF SLOVENIA CAMEROON KUWAIT SOUTH AFRICA CANADA KYRGYZSTAN SPAIN CENTRAL AFRICAN LATVIA SRI LANKA REPUBLIC LEBANON SUDAN CHAD LIBERIA SWEDEN CHILE LIBYAN ARAB JAMAHIRIYA SWITZERLAND CHINA LIECHTENSTEIN SYRIAN ARAB REPUBLIC COLOMBIA LITHUANIA TAJIKISTAN COSTA RICA LUXEMBOURG CÔTE D’IVOIRE MADAGASCAR THAILAND CROATIA MALAWI THE FORMER YUGOSLAV CUBA MALAYSIA REPUBLIC OF MACEDONIA CYPRUS MALI TUNISIA CZECH REPUBLIC MALTA TURKEY DEMOCRATIC REPUBLIC MARSHALL ISLANDS UGANDA OF THE CONGO MAURITANIA UKRAINE DENMARK MAURITIUS UNITED ARAB EMIRATES DOMINICAN REPUBLIC MEXICO UNITED KINGDOM OF ECUADOR MONACO GREAT BRITAIN AND EGYPT MONGOLIA NORTHERN IRELAND EL SALVADOR MONTENEGRO UNITED REPUBLIC ERITREA MOROCCO OF TANZANIA ESTONIA MOZAMBIQUE UNITED STATES OF AMERICA ETHIOPIA MYANMAR URUGUAY FINLAND NAMIBIA UZBEKISTAN FRANCE NETHERLANDS VENEZUELA GABON NEW ZEALAND VIETNAM GEORGIA NICARAGUA YEMEN GERMANY NIGER ZAMBIA GHANA NIGERIA ZIMBABWE The Agency’s Statute was approved on 23 October 1956 by the Conference on the Statute of the IAEA held at United Nations Headquarters, New York; it entered into force on 29 July 1957. The Headquarters of the Agency are situated in Vienna. Its principal objective is “to accelerate and enlarge the contribution of atomic energy to peace, health and prosperity throughout the world’’. DATABASE OF PROMPT GAMMA RAYS FROM SLOW NEUTRON CAPTURE FOR ELEMENTAL ANALYSIS INTERNATIONAL ATOMIC ENERGY AGENCY VIENNA, 2007 COPYRIGHT NOTICE All IAEA scientific and technical publications are protected by the terms of the Universal Copyright Convention as adopted in 1952 (Berne) and as revised in 1972 (Paris). The copyright has since been extended by the World Intellectual Property Organization (Geneva) to include electronic and virtual intellectual property. Permission to use whole or parts of texts contained in IAEA publications in printed or electronic form must be obtained and is usually subject to royalty agreements. Proposals for non-commercial reproductions and translations are welcomed and considered on a case-by-case basis. Enquiries should be addressed to the IAEA Publishing Section at: Sales and Promotion, Publishing Section International Atomic Energy Agency Wagramer Strasse 5 P. O. B o x 1 0 0 1400 Vienna, Austria fax: +43 1 2600 29302 tel.: +43 1 2600 22417 email: [email protected] http://www.iaea.org/books © IAEA, 2007 Printed by the IAEA in Austria January 2007 STI/PUB/1263 IAEA Library Cataloguing in Publication Data Database of prompt gamma rays from slow neutron capture for elemental analysis. — Vienna : International Atomic Energy Agency, 2006. p. ; 24 cm. STI/PUB/1263 ISBN 92–0–101306–X Includes bibliographical references. 1. Gamma rays. 2. Neutron beams. 3. Neutrons — Capture. 4. Neutron cross sections. I. International Atomic Energy Agency. IAEAL 06–00466 FOREWORD The increasing importance of prompt gamma ray activation analysis (PGAA) in a broad range of applications is evident, and has been emphasized at many meetings related to this topic. Furthermore, an Advisory Group Meeting (AGM) for the Coordination of the International Network of Nuclear Structure and Decay Data Evaluators concluded that there is a need for a complete library of gamma ray and cross-section data from cold and thermal neutron capture (the AGM was held in Budapest, 14–18 October 1996); this AGM also recommended the organization of an IAEA Coordinated Research Project (CRP) on this subject. The nuclear data programmes of the IAEA arose as a consequence of the advisory reviews of the International Nuclear Data Committee (INDC). At a biennial meeting in 1997, the INDC strongly recommended that the IAEA support new measurements and update the database on the analysis of prompt gamma ray activation induced by neutrons. As a consequence of the various recommendations, a CRP, entitled Development of a Database for Prompt Gamma Ray Neutron Activation Analysis (PGAA), was initiated in 1999. Prior to this project, several consultants had defined the scope, objectives and tasks of this CRP, as approved subsequently by the IAEA. Each CRP participant assumed responsibility for the execution of specific tasks. The results of their work and of other research were discussed and approved by the participants in Research Coordination Meetings (RCMs) held in 2000, 2001 and 2003. Prompt gamma ray activation analysis is a non-destructive radioanalytical method capable of rapid or simultaneous in situ multielement analyses across the entire periodic table, from hydrogen to uranium. However, inaccurate and incomplete data have been a significant hindrance in the qualitative and quantitative analyses of complicated neutron capture gamma spectra by means of PGAA. Therefore, the main goal of the CRP was to improve the quality and quantity of the required data in order to make possible the reliable application of PGAA in fields such as materials science, chemistry, geology, mining, archaeology, the environment, food analysis and medicine. This aim was achieved due to the dedicated work and effort of the participants. The CD-ROM included with this publication contains the database, retrieval system, three RCM reports, and other important electronic documents related to the project (see also Chapter 8). The IAEA wishes to thank all CRP participants who contributed to the success of this project and to the formulation of this publication. The IAEA is grateful to R.B. Firestone for his leading role in the evolution of this CRP and for his comprehensive compilation, analysis and provision of the adopted database, and to V. Zerkin for the software developments associated with the retrieval system. An essential component of this data compilation is the extensive set of new measurements of neutron capture gamma ray energies and intensities undertaken at the Institute of Isotope and Surface Chemistry, Budapest. The IAEA is also grateful to S.C. Frankle and M.A. Lone for their active involvement as consultants at some of the meetings. The technical officer responsible for the CRP, this publication and the resulting database was R. Paviotti-Corcuera of the Division of Physical and Chemical Sciences. Contributors: Choi, H.D. Seoul National University, Republic of Korea Firestone, R.B. Lawrence Berkeley National Laboratory, United States of America Lindstrom, R.M. National Institute for Standards and Technology, United States of America Molnár, G.L. Institute of Isotope and Surface Chemistry, Hungarian Academy of Sciences, Hungary Mughabghab, S.F. Brookhaven National Laboratory, United States of America Paviotti-Corcuera, R. International Atomic Energy Agency Révay, Z. Institute of Isotope and Surface Chemistry, Hungarian Academy of Sciences, Hungary Trkov, A. International Atomic Energy Agency Zerkin, V. International Atomic Energy Agency Zhou, Chunmei China Nuclear Data Centre, China EDITORIAL NOTE This database has been edited by the editorial staff of the IAEA to the extent considered necessary for the reader’s assistance. The views expressed remain, however, the responsibility of the named authors. In addition, the views are not necessarily those of the governments of the nominating Member States or of the nominating organizations. Although great care has been taken to maintain the accuracy of information contained in this publication, neither the IAEA nor its Member States assume any responsibility for consequences which may arise from its use. The use of particular designations of countries or territories does not imply any judgement by the publisher, the IAEA, as to the legal status of such countries or territories, of their authorities and institutions or of the delimitation of their boundaries. The mention of names of specific companies or products (whether or not indicated as registered) does not imply any intention to infringe proprietary rights, nor should it be construed as an endorsement or recommendation on the part of the IAEA. The authors are responsible for having obtained the necessary permission for the IAEA to reproduce, translate or use material from sources already protected by copyrights. Material prepared by authors who are in contractual relation with governments is copyrighted by the IAEA, as publisher, only to the extent permitted by the appropriate national regulations. CONTENTS CHAPTER 1. INTRODUCTION R.M. Lindstrom . 1 References to Chapter 1 . 2 CHAPTER 2. NOMENCLATURE, WESTCOTT gW FACTORS AND NEUTRON SPECTRAL SHAPE DEPENDENT FORMALISM H.D. Choi, A. Trkov . 5 2.1. Introduction. 5 2.2. Definitions and nomenclature. 5 2.2.1. Prompt k0 factors . 5 2.2.2. Elemental cross-sections . 5 2.2.3. Effective capture cross-sections . 6 2.2.4. Thermal and epithermal fluxes. 6 2.2.5. Westcott g factors . 7 2.3. Generalized formalism. 12 2.3.1. Capture rates . 12 2.3.2.
Recommended publications
  • Neutron Interactions and Dosimetry Outline Introduction Tissue
    Outline • Neutron dosimetry Neutron Interactions and – Thermal neutrons Dosimetry – Intermediate-energy neutrons – Fast neutrons Chapter 16 • Sources of neutrons • Mixed field dosimetry, paired dosimeters F.A. Attix, Introduction to Radiological • Rem meters Physics and Radiation Dosimetry Introduction Tissue composition • Consider neutron interactions with the majority tissue elements H, O, C, and N, and the resulting absorbed dose • Because of the short ranges of the secondary charged particles that are produced in such interactions, CPE is usually well approximated • Since no bremsstrahlung x-rays are generated, the • The ICRU composition for muscle has been assumed in absorbed dose can be assumed to be equal to the most cases for neutron-dose calculations, lumping the kerma at any point in neutron fields at least up to 1.1% of “other” minor elements together with oxygen to an energy E ~ 20 MeV make a simple four-element (H, O, C, N) composition Neutron kinetic energy Neutron kinetic energy • Neutron fields are divided into three • Thermal neutrons, by definition, have the most probable categories based on their kinetic energy: kinetic energy E=kT=0.025eV at T=20C – Thermal (E<0.5 eV) • Neutrons up to 0.5eV are considered “thermal” due to simplicity of experimental test after they emerge from – Intermediate-energy (0.5 eV<E<10 keV) moderator material – Fast (E>10 keV) • Cadmium ratio test: • Differ by their primary interactions in tissue – Gold foil can be activated through 197Au(n,)198Au interaction and resulting biological effects
    [Show full text]
  • Neutron Activation and Prompt Gamma Intensity in Ar/CO $ {2} $-Filled Neutron Detectors at the European Spallation Source
    Neutron activation and prompt gamma intensity in Ar/CO2-filled neutron detectors at the European Spallation Source E. Diana,b,c,∗, K. Kanakib, R. J. Hall-Wiltonb,d, P. Zagyvaia,c, Sz. Czifrusc aHungarian Academy of Sciences, Centre for Energy Research, 1525 Budapest 114., P.O. Box 49., Hungary bEuropean Spallation Source ESS ERIC, P.O Box 176, SE-221 00 Lund, Sweden cBudapest University of Technology and Economics, Institute of Nuclear Techniques, 1111 Budapest, M}uegyetem rakpart 9. dMid-Sweden University, SE-851 70 Sundsvall, Sweden Abstract Monte Carlo simulations using MCNP6.1 were performed to study the effect of neutron activation in Ar/CO2 neutron detector counting gas. A general MCNP model was built and validated with simple analytical calculations. Simulations and calculations agree that only the 40Ar activation can have a considerable effect. It was shown that neither the prompt gamma intensity from the 40Ar neutron capture nor the produced 41Ar activity have an impact in terms of gamma dose rate around the detector and background level. Keywords: ESS, neutron detector, B4C, neutron activation, 41Ar, MCNP, Monte Carlo simulation 1. Introduction Ar/CO2 is a widely applied detector counting gas, with long history in ra- diation detection. Nowadays, the application of Ar/CO2-filled detectors is ex- tended in the field of neutron detection as well. However, the exposure of arXiv:1701.08117v2 [physics.ins-det] 16 Jun 2017 Ar/CO2 counting gas to neutron radiation carries the risk of neutron activa- tion. Therefore, detailed consideration of the effect and amount of neutron ∗Corresponding author Email address: [email protected] (E.
    [Show full text]
  • TUTORIAL on NEUTRON PHYSICS in DOSIMETRY S. Pomp1
    TUTORIAL ON NEUTRON PHYSICS IN DOSIMETRY S. Pomp1,* 1 Department of physics and astronomy, Uppsala University, Box 516, 751 20 Uppsala, Sweden. *Corresponding author. E‐mail address: [email protected] (S.Pomp) Abstract: Almost since the time of the discovery of the neutron more than 70 years ago, efforts have been made to understand the effects of neutron radiation on tissue and, eventually, to use neutrons for cancer treatment. In contrast to charged particle or photon radiations which directly lead to release of electrons, neutrons interact with the nucleus and induce emission of several different types of charged particles such as protons, alpha particles or heavier ions. Therefore, a fundamental understanding of the neutron‐nucleus interaction is necessary for dose calculations and treatment planning with the needed accuracy. We will discuss the concepts of dose and kerma, neutron‐nucleus interactions and have a brief look at nuclear data needs and experimental facilities and set‐ups where such data are measured. Keywords: Neutron physics; nuclear reactions; kerma coefficients; neutron beams; Introduction Dosimetry is concerned with the ability to determine the absorbed dose in matter and tissue resulting from exposure to directly and indirectly ionizing radiation. The absorbed dose is a measure of the energy deposited per unit mass in the medium by ionizing radiation and is measured in Gray, Gy, where 1 Gy = 1 J/kg. Radiobiology then uses information about dose to assess the risks and gains. A risk is increased probability to develop cancer due to exposure to a certain dose. A gain is exposure of a cancer tumour to a certain dose in order to cure it.
    [Show full text]
  • Concrete Analysis by Neutron-Capture Gamma Rays Using Californium 252
    CONCRETE ANALYSIS BY NEUTRON-CAPTURE GAMMA RAYS USING CALIFORNIUM 252 Dick Duffey, College of Engineering, University of Maryland; Peter F. Wiggins, Naval Systems Engineering Department, U.S. Naval Academy; Frank E. Senftle, U.S. Geological Survey; and A. A. El Kady, United Arab Republic Atomic Energy Establishment, Cairo The feasibility of analyzing concrete and cement by a measurement of the neutron-capture or prompt gamma rays was investigated; a 100-ug californium-252 source was used to supply the neutrons. A lithium drifted germanium crystal detected the capture gamma rays emitted. The capture gamma rays from cement, sand, and 3 coarse aggregates-quartzite gravel, limestone, and diabase--:were studied. Concrete blocks made from these materials were then tested. The capture gamma ray response of the calcium, silicon, and iron in the concrete blocks was in accord with the elements identified in the mix materials. The principal spectral lines used were the 6.42 MeV line of calcium, the 4.93 MeV line of silicon, and the doublet of iron at about 7 .64 MeV. The aluminum line at 7. 72 MeV was ob­ served in some cases but at a lower intensity with the limited electronic equipment available. This nuclear spectroscopic technique offers a possi­ ble method of determining the components of sizable concrete samples in a nondestructive, in situ manner. In addition, the neutron-capture gamma ray technique might find application in control of the concrete and cement processes and furnish needed information on production operations and inventories. • FROM THE point of view of the geochemical analyst, concrete may be considered as rock relocated and reformed at the convenience of the engineer.
    [Show full text]
  • Conceptual Design Report Jülich High
    General Allgemeines ual Design Report ual Design Report Concept Jülich High Brilliance Neutron Source Source Jülich High Brilliance Neutron 8 Conceptual Design Report Jülich High Brilliance Neutron Source (HBS) T. Brückel, T. Gutberlet (Eds.) J. Baggemann, S. Böhm, P. Doege, J. Fenske, M. Feygenson, A. Glavic, O. Holderer, S. Jaksch, M. Jentschel, S. Kleefisch, H. Kleines, J. Li, K. Lieutenant,P . Mastinu, E. Mauerhofer, O. Meusel, S. Pasini, H. Podlech, M. Rimmler, U. Rücker, T. Schrader, W. Schweika, M. Strobl, E. Vezhlev, J. Voigt, P. Zakalek, O. Zimmer Allgemeines / General Allgemeines / General Band / Volume 8 Band / Volume 8 ISBN 978-3-95806-501-7 ISBN 978-3-95806-501-7 T. Brückel, T. Gutberlet (Eds.) Gutberlet T. Brückel, T. Jülich High Brilliance Neutron Source (HBS) 1 100 mA proton ion source 2 70 MeV linear accelerator 5 3 Proton beam multiplexer system 5 4 Individual neutron target stations 4 5 Various instruments in the experimental halls 3 5 4 2 1 5 5 5 5 4 3 5 4 5 5 Schriften des Forschungszentrums Jülich Reihe Allgemeines / General Band / Volume 8 CONTENT I. Executive summary 7 II. Foreword 11 III. Rationale 13 1. Neutron provision 13 1.1 Reactor based fission neutron sources 14 1.2 Spallation neutron sources 15 1.3 Accelerator driven neutron sources 15 2. Neutron landscape 16 3. Baseline design 18 3.1 Comparison to existing sources 19 IV. Science case 21 1. Chemistry 24 2. Geoscience 25 3. Environment 26 4. Engineering 27 5. Information and quantum technologies 28 6. Nanotechnology 29 7. Energy technology 30 8.
    [Show full text]
  • 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.
    [Show full text]
  • Sonie Applications of Fast Neutron Activation Analysis of Oxygen
    S E03000182 CTH-RF- 16-5 Sonie Applications of Fast Neutron Activation Analysis of Oxygen Farshid Owrang )52 Akadenmisk uppsats roir avliiggande~ av ilosofie ficentiatexamen i Reaktorf'ysik vid Chalmer's tekniska hiigskola Examinator: Prof. Imre PiAst Handledare: Dr. Anders Nordlund Granskare: Bitr. prof. G~iran Nyrnan Department of Reactor Physics Chalmers University of Technology G6teborg 2003 ISSN 0281-9775 SOME APPLICATIONS OF FAST NEUTRON ACTIVATION OF OXYGE~'N F~arshid Owrang Chalmers University of Technology Departmlent of Reactor Physics SEP-1-412 96 G~iteborg ABSTRACT In this thesis we focus on applications of neutron activation of oxygen for several purposes: A) measuring the water level in a laboratory tank, B) measuring the water flow in a pipe system set-up, C) analysing the oxygen in combustion products formed in a modern gasoline S engine, and D) measuring on-line the amount of oxygen in bulk liquids. A) Water level measurements. The purpose of this work was to perform radiation based water level measurements, aimed at nuclear reactor vessels, on a laboratory scale. A laboratory water tank was irradiated by fast neutrons from a neutron enerator. The water was activated at different water levels and the water level was decreased. The produced gamma radiation was measured using two detectors at different heights. The results showed that the method is suitable for measurement of water level and that a relatively small experimental set-up can be used for developing methods for water level measurements in real boiling water reactors based on activated oxygen in the water. B) Water flows in pipe.
    [Show full text]
  • STUDY of the NEUTRON and PROTON CAPTURE REACTIONS 10,11B(N, ), 11B(P, ), 14C(P, ), and 15N(P, ) at THERMAL and ASTROPHYSICAL ENERGIES
    STUDY OF THE NEUTRON AND PROTON CAPTURE REACTIONS 10,11B(n, ), 11B(p, ), 14C(p, ), AND 15N(p, ) AT THERMAL AND ASTROPHYSICAL ENERGIES SERGEY DUBOVICHENKO*,†, ALBERT DZHAZAIROV-KAKHRAMANOV*,† *V. G. Fessenkov Astrophysical Institute “NCSRT” NSA RK, 050020, Observatory 23, Kamenskoe plato, Almaty, Kazakhstan †Institute of Nuclear Physics CAE MINT RK, 050032, str. Ibragimova 1, Almaty, Kazakhstan *[email protected][email protected] We have studied the neutron-capture reactions 10,11B(n, ) and the role of the 11B(n, ) reaction in seeding r-process nucleosynthesis. The possibility of the description of the available experimental data for cross sections of the neutron capture reaction on 10B at thermal and astrophysical energies, taking into account the resonance at 475 keV, was considered within the framework of the modified potential cluster model (MPCM) with forbidden states and accounting for the resonance behavior of the scattering phase shifts. In the framework of the same model the possibility of describing the available experimental data for the total cross sections of the neutron radiative capture on 11B at thermal and astrophysical energies were considered with taking into account the 21 and 430 keV resonances. Description of the available experimental data on the total cross sections and astrophysical S-factor of the radiative proton capture on 11B to the ground state of 12C was treated at astrophysical energies. The possibility of description of the experimental data for the astrophysical S-factor of the radiative proton capture on 14C to the ground state of 15N at astrophysical energies, and the radiative proton capture on 15N at the energies from 50 to 1500 keV was considered in the framework of the MPCM with the classification of the orbital states according to Young tableaux.
    [Show full text]
  • Energy Deposition by Neutrons
    22.55 “Principles of Radiation Interactions” Neutrons Classification of neutrons by energy Thermal: E < 1 eV (0.025 eV) Epithermal: 1 eV < E < 10 keV Fast: > 10 keV Neutron sources Neutron energies Reactors neutrons in the few keV to several MeV Fusion reactions 14 MeV Large accelerators Hundreds of MeV Energy Deposition by Neutrons • Neutrons are generated over a wide range of energies by a variety of different processes. • Like photons, neutrons are uncharged and do not interact with orbital electrons. • Neutrons can travel considerable distances through matter without interacting. • Neutrons will interact with atomic nuclei through several mechanisms. o Elastic scatter o Inelastic scatter o Nonelastic scatter o Neutron capture o Spallation • The type of interaction depends on the neutron energy Radiation Interactions: neutrons Page 1 of 8 22.55 “Principles of Radiation Interactions” Cross Sections • Because mass attenuation coefficients, µ/ρ (cm2/g) have dimensions of cm2 in the numerator, they have come to be called “cross sections”. • Cross sections do not represent a physical area, but a probability of an interaction. • Cross sections usually expressed in the unit, barn: (10-24 cm2) • The atomic cross sections can be derived from the mass attenuation coefficient. Photons Cross sections are attenuation coefficients, expressed at the atom level (Probability of interaction per atom) ρ N = atom density (#atoms/cm3) N = N A A A 0 2 σA = atomic cross section (cm /atom) 23 N0 = 6.02 x 10 atoms/mole ρ = g/cm3 µ = N A σ A A = g/mole ρ µ = N σ A 0 A µ N σ ⎛ µ ⎞⎛ A ⎞ 0 A ⎜ ⎟⎜ ⎟ = σ A = ⎜ ⎟⎜ ⎟ ρ A ⎝ ρ ⎠⎝ N 0 ⎠ Radiation Interactions: neutrons Page 2 of 8 22.55 “Principles of Radiation Interactions” Neutron Cross Sections Analogous to photons • Neutrons interact by different mechanisms depending on the neutron energy and the material of the absorber o Scattering • elastic • inelastic o Capture • Each energy loss mechanism has a cross section • Neutron cross sections expressed in barns (1 barn = 10-24 cm2).
    [Show full text]
  • Computing Neutron Capture Rates in Neutron-Degenerate Matter †
    universe Article Computing Neutron Capture Rates in Neutron-Degenerate Matter † Bryn Knight and Liliana Caballero * Department of Physics, University of Guelph, Guelph, ON N1G 2W1, Canada; [email protected] * Correspondence: [email protected] † This paper is based on the talk at the 7th International Conference on New Frontiers in Physics (ICNFP 2018), Crete, Greece, 4–12 July 2018. Received: 28 November 2018; Accepted: 16 January 2019; Published: 18 January 2019 Abstract: Neutron captures are likely to occur in the crust of accreting neutron stars (NSs). Their rate depends on the thermodynamic state of neutrons in the crust. At high densities, neutrons are degenerate. We find degeneracy corrections to neutron capture rates off nuclei, using cross sections evaluated with the reaction code TALYS. We numerically integrate the relevant cross sections over the statistical distribution functions of neutrons at thermodynamic conditions present in the NS crust. We compare our results to analytical calculations of these corrections based on a power-law behavior of the cross section. We find that although an analytical integration can simplify the calculation and incorporation of the results for nucleosynthesis networks, there are uncertainties caused by departures of the cross section from the power-law approach at energies close to the neutron chemical potential. These deviations produce non-negligible corrections that can be important in the NS crust. Keywords: neutron capture; neutron stars; degenerate matter; nuclear reactions 1. Introduction X-ray burst and superburst observations are attributed to accreting neutron stars (NSs) (see, e.g., [1,2]). In such a scenario, a NS drags matter from a companion star.
    [Show full text]
  • Neutron Capture Cross Sections of Cadmium Isotopes
    Neutron Capture Cross Sections of Cadmium Isotopes By Allison Gicking A thesis submitted to Oregon State University In partial fulfillment of the requirements for the degree of Bachelor of Science Presented June 8, 2011 Commencement June 17, 2012 Abstract The neutron capture cross sections of 106Cd, 108Cd, 110Cd, 112Cd, 114Cd and 116Cd were determined in the present project. Four different OSU TRIGA reactor facilities were used to produce redundancy in the results and to measure the thermal cross section and resonance integral separately. When the present values were compared with previously measured values, the differences were mostly due to the kind of detector used or whether or not the samples were natural cadmium. Some of the isotopes did not have any previously measured values, and in that case, new information about the cross sections of those cadmium isotopes has been provided. Table of Contents I. Introduction………………………………………………………………….…….…1 II. Theory………………………………………………………………………...…...…3 1. Neutron Capture…………………………………………………….….……3 2. Resonance Integral vs. Effective Thermal Cross Section…………...………5 3. Derivation of the Activity Equations…………………………………....…..8 III. Methods………………………………………………………….................…...…...12 1. Irradiation of the Samples………………………………………….….....…12 2. Sample Preparation and Parameters………………..………...………..……16 3. Efficiency Calibration of Detectors…………………………..………....…..18 4. Data Analysis…………………………………...…….………………...…..19 5. Absorption by 113Cd……………………………………...……...….………20 IV. Results………………………………………………….……………..……….…….22
    [Show full text]
  • Direct Measurement of the Neutron
    Louisiana State University LSU Digital Commons LSU Doctoral Dissertations Graduate School 1-9-2020 Stellar Nucleosynthesis: Direct Measurement of the Neutron- Capture Cross Sections of Stable Germanium Isotopes and Design of a Next Generation Ion Trap for the Study of Beta- Delayed Neutron Emission Alexander Laminack Louisiana State University and Agricultural and Mechanical College Follow this and additional works at: https://digitalcommons.lsu.edu/gradschool_dissertations Part of the Instrumentation Commons, Nuclear Commons, Physical Processes Commons, and the Stars, Interstellar Medium and the Galaxy Commons Recommended Citation Laminack, Alexander, "Stellar Nucleosynthesis: Direct Measurement of the Neutron-Capture Cross Sections of Stable Germanium Isotopes and Design of a Next Generation Ion Trap for the Study of Beta- Delayed Neutron Emission" (2020). LSU Doctoral Dissertations. 5131. https://digitalcommons.lsu.edu/gradschool_dissertations/5131 This Dissertation is brought to you for free and open access by the Graduate School at LSU Digital Commons. It has been accepted for inclusion in LSU Doctoral Dissertations by an authorized graduate school editor of LSU Digital Commons. For more information, please [email protected]. STELLAR NUCLEOSYNTHESIS: DIRECT MEASUREMENT OF THE NEUTRON-CAPTURE CROSS SECTIONS OF STABLE GERMANIUM ISOTOPES AND DESIGN OF A NEXT GENERATION ION TRAP FOR THE STUDY OF β-DELAYED NEUTRON EMISSION A Dissertation Submitted to the Graduate Faculty of the Louisiana State University and Agricultural and Mechanical College in partial fulfillment of the requirements for the degree of Doctor of Philosophy in The Department of Physics and Astronomy by Alexander Laminack B. S., The Unviersity of Alabama, 2015 May 2020 To my wife and son: Kristy Allen Alexander Laminack and Daniel Allen Laminack.
    [Show full text]