Neutron Fluence Measurements
Total Page:16
File Type:pdf, Size:1020Kb
Load more
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 -
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. -
Status of ITER Neutron Diagnostic Development
INSTITUTE OF PHYSICS PUBLISHING and INTERNATIONAL ATOMIC ENERGY AGENCY NUCLEAR FUSION Nucl. Fusion 45 (2005) 1503–1509 doi:10.1088/0029-5515/45/12/005 Status of ITER neutron diagnostic development A.V. Krasilnikov1, M. Sasao2, Yu.A. Kaschuck1, T. Nishitani3, P. Batistoni4, V.S. Zaveryaev5, S. Popovichev6, T. Iguchi7, O.N. Jarvis6,J.Kallne¨ 8, C.L. Fiore9, A.L. Roquemore10, W.W. Heidbrink11, R. Fisher12, G. Gorini13, D.V. Prosvirin1, A.Yu. Tsutskikh1, A.J.H. Donne´14, A.E. Costley15 and C.I. Walker16 1 SRC RF TRINITI, Troitsk, Russian Federation 2 Tohoku University, Sendai, Japan 3 JAERI, Tokai-mura, Japan 4 FERC, Frascati, Italy 5 RRC ‘Kurchatov Institute’, Moscow, Russian Federation 6 Euratom/UKAEA Fusion Association, Culham Science Center, Abingdon, UK 7 Nagoya University, Nagoya, Japan 8 Uppsala University, Uppsala, Sweden 9 PPL, MIT, Cambridge, MA, USA 10 PPPL, Princeton, NJ, USA 11 UC Irvine, Los Angeles, CA, USA 12 GA, San Diego, CA, USA 13 Milan University, Milan, Italy 14 FOM-Rijnhuizen, Netherlands 15 ITER IT, Naka Joint Work Site, Naka, Japan 16 ITER IT, Garching Joint Work Site, Garching, Germany E-mail: [email protected] Received 7 December 2004, accepted for publication 14 September 2005 Published 22 November 2005 Online at stacks.iop.org/NF/45/1503 Abstract Due to the high neutron yield and the large plasma size many ITER plasma parameters such as fusion power, power density, ion temperature, fast ion energy and their spatial distributions in the plasma core can be measured well by various neutron diagnostics. Neutron diagnostic systems under consideration and development for ITER include radial and vertical neutron cameras (RNC and VNC), internal and external neutron flux monitors (NFMs), neutron activation systems and neutron spectrometers. -
An Integrated Model for Materials in a Fusion Power Plant: Transmutation, Gas Production, and Helium Embrittlement Under Neutron Irradiation
Home Search Collections Journals About Contact us My IOPscience An integrated model for materials in a fusion power plant: transmutation, gas production, and helium embrittlement under neutron irradiation This article has been downloaded from IOPscience. Please scroll down to see the full text article. 2012 Nucl. Fusion 52 083019 (http://iopscience.iop.org/0029-5515/52/8/083019) View the table of contents for this issue, or go to the journal homepage for more Download details: IP Address: 193.52.216.130 The article was downloaded on 13/11/2012 at 13:27 Please note that terms and conditions apply. IOP PUBLISHING and INTERNATIONAL ATOMIC ENERGY AGENCY NUCLEAR FUSION Nucl. Fusion 52 (2012) 083019 (12pp) doi:10.1088/0029-5515/52/8/083019 An integrated model for materials in a fusion power plant: transmutation, gas production, and helium embrittlement under neutron irradiation M.R. Gilbert, S.L. Dudarev, S. Zheng, L.W. Packer and J.-Ch. Sublet EURATOM/CCFE Fusion Association, Culham Centre for Fusion Energy, Abingdon, Oxfordshire OX14 3DB, UK E-mail: [email protected] Received 16 January 2012, accepted for publication 11 July 2012 Published 1 August 2012 Online at stacks.iop.org/NF/52/083019 Abstract The high-energy, high-intensity neutron fluxes produced by the fusion plasma will have a significant life-limiting impact on reactor components in both experimental and commercial fusion devices. As well as producing defects, the neutrons bombarding the materials initiate nuclear reactions, leading to transmutation of the elemental atoms. Products of many of these reactions are gases, particularly helium, which can cause swelling and embrittlement of materials. -
Organic Seminar Abstracts
L I B RA FLY OF THE U N IVERSITY OF 1LLI NOIS Q.54-1 Ii£s 1964/65 ,t.l P Return this book on or before the Latest Date stamped below. Theft, mutilation, and underlining of books are reasons for disciplinary action and may result in dismissal from the University. University of Illinois Library OCfcfcsrm L161— O-1096 Digitized by the Internet Archive in 2012 with funding from University of Illinois Urbana-Champaign http://archive.org/details/organicsemi1964651univ s ORGANIC SEMINAR ABSTRACTS 196^-65 Semester I Department of Chemistry and Chemical Engineering University of Illinois ' / SEMINAR TOPICS I Semester I96U-I965 f"/ ( Orientation in Sodium and Potassium Metalations of Aromatic Compounds Earl G. Alley 1 Structure of Cyclopropane Virgil Weiss 9 Vinylidenes and Vinylidenecarbenes Joseph C. Catlin 17 Diazene Intermediates James A. Bonham 25 Perfluoroalkyl and Polyfluoroalkyl Carbanions J. David Angerer 3^ Free Radical Additions to Allenes Raymond Feldt 43 The Structure and Biosynthesis of Quassin Richard A. Larson 52 The Decomposition of Perester Compounds Thomas Sharpe 61 The Reaction of Di-t -Butyl Peroxide with Simple Alkyl, Benzyl and Cyclic Ethers R. L. Keener 70 Rearrangements and Solvolysis in Some Allylic Systems Jack Timberlake 79 Longifolene QQ Michael A. Lintner 00 Hydrogenation ! Homogeneous Catalytic Robert Y. Ning 9° c c Total Synthesis of ( -) -Emetime R. Lambert 1* Paracyclophanes Ping C. Huang 112 Mechanism of the Thermal Rearrangement of Cyclopropane George Su 121 Some Recent Studies of the Photochemistry of Cross -Conjugated Cyclohexadienones Elizabeth McLeister 130 The Hammett Acidity Function R. P. Quirk 139 Homoaromaticity Roger A. -
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. -
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. -
Neutronic Model of a Fusion Neutron Source
STATIC NEUTRONIC CALCULATION OF A FUSION NEUTRON SOURCE S.V. Chernitskiy1, V.V. Gann1, O. Ågren2 1“Nuclear Fuel Cycle” Science and Technology Establishment NSC KIPT, Kharkov, Ukraine; 2Uppsala University, Ångström Laboratory, Uppsala, Sweden The MCNPX numerical code has been used to model a fusion neutron source based on a combined stellarator- mirror trap. Calculation results for the neutron flux and spectrum inside the first wall are presented. Heat load and irradiation damage on the first wall are calculated. PACS: 52.55.Hc, 52.50.Dg INTRODUCTION made in Ref. [5] indicates that under certain conditions Powerful sources of fusion neutrons from D-T nested magnetic surfaces could be created in a reaction with energies ~ 14 MeV are of particular stellarator-mirror machine. interest to test suitability of materials for use in fusion Some fusion neutrons are generated outside the reactors. Developing materials for fusion reactors has main part near the injection point. There is a need of long been recognized as a problem nearly as difficult protection from these neutrons. and important as plasma confinement, but it has The purpose is to calculate the neutron spectrum received only a fraction of attention. The neutron flux in inside neutron exposing zone of the installation and a fusion reactor is expected to be about 50-100 times compute the radial leakage of neutrons through the higher than in existing pressurized water reactors. shield. Furthermore, the high-energy neutrons will produce Another problem studied in the paper concerns to hydrogen and helium in various nuclear reactions that the determination of the heat load and irradiation tend to form bubbles at grain boundaries of metals and damage of the first wall of the device, where will be a result in swelling, blistering or embrittlement. -
Revamping Fusion Research Robert L. Hirsch
Revamping Fusion Research Robert L. Hirsch Journal of Fusion Energy ISSN 0164-0313 Volume 35 Number 2 J Fusion Energ (2016) 35:135-141 DOI 10.1007/s10894-015-0053-y 1 23 Your article is protected by copyright and all rights are held exclusively by Springer Science +Business Media New York. This e-offprint is for personal use only and shall not be self- archived in electronic repositories. If you wish to self-archive your article, please use the accepted manuscript version for posting on your own website. You may further deposit the accepted manuscript version in any repository, provided it is only made publicly available 12 months after official publication or later and provided acknowledgement is given to the original source of publication and a link is inserted to the published article on Springer's website. The link must be accompanied by the following text: "The final publication is available at link.springer.com”. 1 23 Author's personal copy J Fusion Energ (2016) 35:135–141 DOI 10.1007/s10894-015-0053-y POLICY Revamping Fusion Research Robert L. Hirsch1 Published online: 28 January 2016 Ó Springer Science+Business Media New York 2016 Abstract A fundamental revamping of magnetic plasma Introduction fusion research is needed, because the current focus of world fusion research—the ITER-tokamak concept—is A practical fusion power system must be economical, virtually certain to be a commercial failure. Towards that publically acceptable, and as simple as possible from a end, a number of technological considerations are descri- regulatory standpoint. In a preceding paper [1] the ITER- bed, believed important to successful fusion research. -
Fusion: the Way Ahead
Fusion: the way ahead Feature: Physics World March 2006 pages 20 - 26 The recent decision to build the world's largest fusion experiment - ITER - in France has thrown down the gauntlet to fusion researchers worldwide. Richard Pitts, Richard Buttery and Simon Pinches describe how the Joint European Torus in the UK is playing a key role in ensuring ITER will demonstrate the reality of fusion power At a Glance: Fusion power • Fusion is the process whereby two light nuclei bind to form a heavier nucleus with the release of energy • Harnessing fusion on Earth via deuterium and tritium reactions would lead to an environmentally friendly and almost limitless energy source • One promising route to fusion power is to magnetically confine a hot, dense plasma inside a doughnut-shaped device called a tokamak • The JET tokamak provides a vital testing ground for understanding the physics and technologies necessary for an eventual fusion reactor • ITER is due to power up in 2016 and will be the next step towards a demonstration fusion power plant, which could be operational by 2035 By 2025 the Earth's population is predicted to reach eight billion. By the turn of the next century it could be as many as 12 billion. Even if the industrialized nations find a way to reduce their energy consumption, this unprecedented increase in population - coupled with rising prosperity in the developing world - will place huge demands on global energy supplies. As our primary sources of energy - fossil fuels - begin to run out, and burning them causes increasing environmental concerns, the human race faces the challenge of finding new energy sources. -
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. -
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).