DOCSLIB.ORG

Neutron Flux and Energy Characterization of a Plutonium-Beryllium Isotopic Neutron Source by Monte Carlo Simulation with Verification Yb Neutron Activation Analysis

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Neutron Flux and Energy Characterization of a Plutonium-Beryllium Isotopic Neutron Source by Monte Carlo Simulation with Verification Yb Neutron Activation Analysis UNLV Theses, Dissertations, Professional Papers, and Capstones 8-2010 Neutron flux and energy characterization of a plutonium-beryllium isotopic neutron source by Monte Carlo simulation with verification yb neutron activation analysis Zachary R. Harvey University of Nevada, Las Vegas Follow this and additional works at: https://digitalscholarship.unlv.edu/thesesdissertations Part of the Medicine and Health Sciences Commons, and the Nuclear Commons Repository Citation Harvey, Zachary R., "Neutron flux and energy characterization of a plutonium-beryllium isotopic neutron source by Monte Carlo simulation with verification by neutron activation analysis" (2010). UNLV Theses, Dissertations, Professional Papers, and Capstones. 900. http://dx.doi.org/10.34917/2242920 This Thesis is protected by copyright and/or related rights. It has been brought to you by Digital Scholarship@UNLV with permission from the rights-holder(s). You are free to use this Thesis in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s) directly, unless additional rights are indicated by a Creative Commons license in the record and/ or on the work itself. This Thesis has been accepted for inclusion in UNLV Theses, Dissertations, Professional Papers, and Capstones by an authorized administrator of Digital Scholarship@UNLV. For more information, please contact [email protected]. NEUTRON FLUX AND ENERGY CHARACTERIZATION OF A PLUTONIUM- BERYLLIUM ISOTOPIC NEUTRON SOURCE BY MONTE CARLO SIMULATION WITH VERIFICATION BY NEUTRON ACTIVATION ANALYSIS by Zachary R. Harvey Bachelor of Science Purdue University 2008 A thesis submitted in partial fulfillment of the requirements for the Master of Science in Health Physics Department of Health Physics and Diagnostic Sciences School of Allied Health Sciences Division of Health Sciences Graduate College University of Nevada, Las Vegas August 2010 Copyright by Zachary Harvey 2010 All Rights Reserved THE GRADUATE COLLEGE We recommend the thesis prepared under our supervision by Zachary R. Harvey entitled Neutron Flux and Energy Characterization of a Plutonium-Beryllium Isotopic Neutron Source by Monte Carlo Simulation with Verification by Neutron Activation Analysis be accepted in partial fulfillment of the requirements for the degree of Master of Science in Health Physics Health Physics and Diagnostic Sciences Ralf Sudowe, Committee Co-chair Phillip Patton, Committee Co-chair Gary Cerefice, Committee Member Patricia Paviett-Hartman, Graduate Faculty Representative Ronald Smith, Ph. D., Vice President for Research and Graduate Studies and Dean of the Graduate College August 2010 ii ABSTRACT Neutron Flux and Energy Characterization of a Plutonium-Beryllium Isotopic Neutron Source by Monte Carlo Simulation with Verification by Neutron Activation Analysis by Zachary Russel Harvey Dr. Ralf Sudowe, Committee Chair Assistant Professor of Health Physics University of Nevada, Las Vegas The purpose of this research was to characterize the neutron energy distribution and flux emitted from the UNLV plutonium-beryllium source, serial number MRC-N-W PuBe 453. This was accomplished through the use of the MCNPX/5 Monte-Carlo particle transport code to simulate radiation interactions within the physical environment of the source and its surroundings. The moderating drum currently containing the source as well as all of the sampling ports were accurately modeled in MCNPX/5. This geometry was then used to simulate the neutron interactions taking place in these geometries. The results of the simulations were then verified by the use of specifically chosen activation detectors and threshold foils designed to accurately convey information on the energy distribution and flux of the neutrons present at multiple sampling locations. iii TABLE OF CONTENTS ABSTRACT……………………………………………………………………………...iii LIST OF TABLES……………………………………………………………..…………vi LIST OF FIGURES……...……………………………………………………………....vii CHAPTER 1 INTRODUCTION...………………………………………………………1 Neutron Sources.........…....………………………………………………………..4 Monte Carlo Simulations…………………….……………………………............6 Neutron Activation .…...…………………...……………………………………..7 Activation Detector Materials………………...…………………………………...9 Literature Review………………………….....…………………………………..13 Scope of Work……………………………...……………………………………17 CHAPTER 2 MONTE CARLO………………….…………………………………….18 SOURCES4C….…………………………………………………………………18 MCNPX………………………………………………………………………….22 CHAPTER 3 NEUTRON ACTIVATION FOILS………………………...……………31 Theory………………………….………………………………………………...31 Materials & Methods………….…………………………………………………33 Counting Methods…………...…………………………………………………..35 Irradiation Scheme……….………………………………………………………36 CHAPTER 4 RESULTS & DISCUSSION…………………………………………….41 Gold (Au) Foil Irradiations………….…………………………………………...41 Indium (In) Foil Irradiations………….………………………………………….45 Error….……………………………....…………………………………………..52 CHAPTER 5 CONTINUATION OF RESEARCH…………………………………….54 Conclusion…...…………………………………………………………………..54 Future Research……...…………………………………………………………..54 APPENDIX 1 SOURCES4C DATA………………………………………………….....56 APPENDIX 2 MODERATING BARREL DIMENSIONS……………………………..59 APPENDIX 3 ACTIVATION CALCULATION DATA……………………………….60 APPENDIX 4 MCNPX DATA………………………………………………………….61 APPENDIX 5 MCNPX INPUT DECKS………………………………………………...68 BIBLIOGRAPHY………………………………………………………………………..75 iv VITA……………………………………………………………………………………..76 v LIST OF TABLES Table 1 Average Neutron Energies Originating at Source…..……….…...…………..5 Table 2 Materials Useful as Slow Neutron Activation Detectors…...……...………..11 Table 3 Input Radionuclide Compositions for SOURCES4C…..…………...……....20 Table 4 PUBE Source Outer Dimensions……………………………………...…….21 Table 5 Gold (Au) Neutron Reactions…………………………………………...…..34 Table 6 Indium (In) Neutron Reactions…………………………………………...…35 Table 7 Aluminum (Al) Threshold Reactions……………………………………......37 Table 8 Irradiation Scheme………………………………………………………......40 Table 9 Comparison of Activity and Flux of Au foils in CT position…………….....41 Table 10 Comparison of Activity and Flux of Au foils in 8 in position……………....44 Table 11 Comparison of Activity and Flux of In foils in CT position…………..….....46 Table 12 Comparison of Activity and Flux of In foils in Y position………………….48 Table 13 Comparison of Activity and Flux of In foils in 5in position……………...…50 Table 14 Metals Foils for Future Irradiation…………………………..........................55 vi LIST OF FIGURES Figure 2.1 UNLV Pu-Be Neutron Source…..…………………………………...….19 Figure 2.2 Comparison of SOURCES4C Results…..…………………………...….21 Figure 2.3 Histogram of Neutron Energy vs. Flux at the Source…..…………….....22 Figure 2.4 MCNPX Irradiation Geometry in X,Y Direction..………………………23 Figure 2.5 MCNPX Irradiation Geometry in X,Z Direction..……………………....24 Figure 2.6 MCNPX Irradiation Geometry in Y,Z Direction…..…………………....25 Figure 2.7 Flux vs. Energy Bin for All Sampling Ports by Location…..…………...26 Figure 2.8 Flux vs. Energy Bin for CT Position….…………………………………27 Figure 2.9 Flux vs. Energy Bin for 8in Position….…………………………………27 Figure 2.10 Flux vs. Energy Bin for 5in Position…...………………………………..28 Figure 2.11 Flux vs. Energy Bin for 2in Position…...………………………………..28 Figure 2.12 Flux vs. Energy Bin for Y Position…...………...………….…………....29 Figure 2.13 Comparison of Neutron Flux vs. Energy for Cd and Non-Covered Foil..30 Figure 3.1 Au-198 Decay Scheme….……………………………………………….34 Figure 3.2 Aluminum Activation Foil Sample Holder…..……………………….....37 Figure 4.1 Calc and Exp Thermal and Epi-Thermal Flux CT Position…..……...….42 Figure 4.2 Calc and Exp Thermal and Epi-Thermal Flux 8in Position…..……...….44 Figure 4.3 Calc and Exp Thermal, Epi-Thermal, Relativistic Flux for In CT Psn.....45 Figure 4.4 Calc and Exp Thermal, Epi-Thermal, Relativistic Flux for In Y Psn…...48 Figure 4.5 Calc and Exp Thermal, Epi-Thermal, Relativistic Flux for In 5in Psn….50 vii ACKNOWLEDGEMENTS I would like to thank Dr. Ralf Sudowe, coffee, and everyone else who helped me in the entirety of my thesis project. My parents deserve a special thank you for all of their support and encouragement throughout my entire education. I would also like to apologize to my parents for moving across the county following the completion of my education. viii CHAPTER 1 INTRODUCTION Neutron Interactions The discovery of neutrons dates back to 1931, when German scientists Walther Bothe and Herbert Becker found that if energetic alpha particles emitted from polonium collided with certain light elements, specifically beryllium, boron, or lithium, an unusually penetrating radiation was produced. Although it was mistaken for gamma radiation at the time, the two scientists had created the first man-made isotopic neutron source. In 1932, James Chadwick performed a series of experiments showing that the gamma ray hypothesis of Bothe and Becker was not possible. He suggested that the radiation consisted of an uncharged particle with approximately the same mass as a proton. Neutrons may be produced in several ways, such as: nuclear fission, nuclear fusion, accelerating devices that induce nuclear reactions involving charged particles and gamma-rays, and the interaction of alpha and gamma radiation with nuclei that results in neutron emission. Depending on how the neutrons are produced, their potential energy distribution ranges from a few tenths of eV to several GeV. However, due to the nature of this type of radiation the energy of the neutron produced at the source will most likely not be the energy of the particle that
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
    [Show full text]
  • MASTER 9700 South Cass Avenue Argonne, Illinois 60439 USA
    ANL/KDH—SO DE84 001440 ANL/NDM-80 NEUTRON TOTAL CROSS SECTION MEASUREMENTS IN THE ENERGY REGION FROM 47 key to 20 MeV* by W. P. Poenitz and J. F. Whalon Applied Physics Division May, 1983 *This work supported by the U.S. Department of Energy Argonne National Laboratory MASTER 9700 South Cass Avenue Argonne, Illinois 60439 USA fflSTRtBtfUOU OF miS DOCUMENT IS UNLIMITED NUCLEAR DATA AMD MEASUREMENTS SERIES The Nuclear Data and Measurements Series presents results of studies in the field of microscopic nuclear data. The primary objective is the dissemination of information in the comprehensive form required for nuclear technology applications. This Series is devoted to: a) measured microscopic nuclear parameters, b) experimental techniques and facilities employed in measurements, c) the analysis, correlation and interpretation of nuclear data, and d) the evaluation of nuclear data. Contributions to this Series are reviewed to assure technical competence and, unless otherwise stated, the contents can be formally referenced. This Series does not supplant formal journal publication but it does provide the more extensive informa- tion required for technological applications (e.g., tabulated numerical data) in a timely manner. DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or retpoosi- bility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Refer- ence herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recom- mendation, or favoring by the United States Government or any agency thereof.
    [Show full text]
  • The Periodic Table of Elements
    The Periodic Table of Elements 1 2 6 Atomic Number = Number of Protons = Number of Electrons HYDROGENH HELIUMHe 1 Chemical Symbol NON-METALS 4 3 4 C 5 6 7 8 9 10 Li Be CARBON Chemical Name B C N O F Ne LITHIUM BERYLLIUM = Number of Protons + Number of Neutrons* BORON CARBON NITROGEN OXYGEN FLUORINE NEON 7 9 12 Atomic Weight 11 12 14 16 19 20 11 12 13 14 15 16 17 18 SODIUMNa MAGNESIUMMg ALUMINUMAl SILICONSi PHOSPHORUSP SULFURS CHLORINECl ARGONAr 23 24 METALS 27 28 31 32 35 40 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 POTASSIUMK CALCIUMCa SCANDIUMSc TITANIUMTi VANADIUMV CHROMIUMCr MANGANESEMn FeIRON COBALTCo NICKELNi CuCOPPER ZnZINC GALLIUMGa GERMANIUMGe ARSENICAs SELENIUMSe BROMINEBr KRYPTONKr 39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 RUBIDIUMRb STRONTIUMSr YTTRIUMY ZIRCONIUMZr NIOBIUMNb MOLYBDENUMMo TECHNETIUMTc RUTHENIUMRu RHODIUMRh PALLADIUMPd AgSILVER CADMIUMCd INDIUMIn SnTIN ANTIMONYSb TELLURIUMTe IODINEI XeXENON 85 88 89 91 93 96 98 101 103 106 108 112 115 119 122 128 127 131 55 56 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 CESIUMCs BARIUMBa HAFNIUMHf TANTALUMTa TUNGSTENW RHENIUMRe OSMIUMOs IRIDIUMIr PLATINUMPt AuGOLD MERCURYHg THALLIUMTl PbLEAD BISMUTHBi POLONIUMPo ASTATINEAt RnRADON 133 137 178 181 184 186 190 192 195 197 201 204 207 209 209 210 222 87 88 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 FRANCIUMFr RADIUMRa RUTHERFORDIUMRf DUBNIUMDb SEABORGIUMSg BOHRIUMBh HASSIUMHs MEITNERIUMMt DARMSTADTIUMDs ROENTGENIUMRg COPERNICIUMCn NIHONIUMNh
    [Show full text]
  • Llfltfits Paul Stanek, MST-6
    COAJF- 9 50cDo/-~^0 LA-UR- 9 5-1666 Title: AGE HARDENING IN RAPIDLY SOLIDIFIED AND HOT ISOSTATICALLY PRESSED BERYLLIUM-ALUM1UM SILVER ALLOYS HVAUli Author(s): David H. Carter, MST-6 Andrew McGeorge, MST-6 Loren A. Jacobson, MST-6 llfltfits Paul Stanek, MST-6 IflllS,Ic 8-o° ,S8 si Proceedings of TMS Annual Meeting, Las Vegas, jJffilJSif—- Nevada, February 1995 as-IVUiS' i in Los Alamos NATIONAL LABORATORY Los Alamos National Laboratory, an affirmative action/equal opportunity employer, is operated by the University of California for the U.S. Department of Energy under contract W-7405-ENG-36. By acceptance of this article, the publisher recognizes that the U.S. Government retains a nonexclusive, royalty-free license to publish or reproduce the published form of this contribution, or to allow others to do so, for U.S. Government purposes. The Los Alamos National Laboratory requests that the publisher identify this article as work performed under the auspices of the U.S. Department of Energy* FotmNo.B36R5 MCTOIQimnM f\c mie hAMMr&T 10 i mi in ST26291M1 DISCLAIMER Portions of this document may be illegible in electronic image products. Images are produced from the best available original document. Age Hardening in Rapidly Solidified and Hot Isostatically Pressed Beryllium-Aluminum-Silver Alloys David H. Carter, Andrew C. McGeorge,* Loren A. Jacobson, and Paul W. Stanek Los Alamos National Laboratory, Los Alamos NM 87545 Abstract Three different alloys of beryllium, aluminum and silver were processed to powder by centrifugal atomization in a helium atmosphere. Alloy com• positions were, by weight, 50% Be, 47.5% Al, 2.5% Ag, 50% Be, 47% Al, 3% Ag, and 50% Be, 46% Al, 4% Ag.
    [Show full text]
  • Neutron Scattering Facilities in Europe Present Status and Future Perspectives
    2 ESFRI Physical Sciences and Engineering Strategy Working Group Neutron Landscape Group Neutron scattering facilities in Europe Present status and future perspectives ESFRI scrIPTa Vol. 1 ESFRI Scripta Volume I Neutron scattering facilities in Europe Present status and future perspectives ESFRI Physical Sciences and Engineering Strategy Working Group Neutron Landscape Group i ESFRI Scripta Volume I Neutron scattering facilities in Europe - Present status and future perspectives Author: ESFRI Physical Sciences and Engineering Strategy Working Group - Neutron Landscape Group Scientific editors: Colin Carlile and Caterina Petrillo Foreword Technical editors: Marina Carpineti and Maddalena Donzelli ESFRI Scripta series will publish documents born out of special studies Cover image: Diffraction pattern from the sugar-binding protein Gal3c with mandated by ESFRI to high level expert groups, when of general interest. lactose bound collected using LADI-III at ILL. Picture credits should be given This first volume reproduces the concluding report of an ad-hoc group to D. Logan (Lund University) and M. Blakeley (ILL) mandated in 2014 by the Physical Science and Engineering Strategy Design: Promoscience srl Work Group (PSE SWG) of ESFRI, to develop a thorough analysis of the European Landscape of Research Infrastructures devoted to Neutron Developed on behalf of the ESFRI - Physical Sciences and Engineering Strategy Scattering, and its evolution in the next decades. ESFRI felt the urgency Working Group by the StR-ESFRI project and with the support of the ESFRI of such analysis, since many reactor-based neutron sources will be closed Secretariat down in the next years due to national decisions, while the European The StR-ESFRI project has received funding from the European Union’s Spallation Source (ESS) in Lund will be fully operative only in the mid Horizon 2020 research and innovation programme under grant agreement or late 2020s.
    [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]
  • Uses of Isotopic Neutron Sources in Elemental Analysis Applications
    EG0600081 3rd Conference on Nuclear & Particle Physics (NUPPAC 01) 20 - 24 Oct., 2001 Cairo, Egypt USES OF ISOTOPIC NEUTRON SOURCES IN ELEMENTAL ANALYSIS APPLICATIONS A. M. Hassan Department of Reactor Physics Reactors Division, Nuclear Research Centre, Atomic Energy Authority. Cairo-Egypt. ABSTRACT The extensive development and applications on the uses of isotopic neutron in the field of elemental analysis of complex samples are largely occurred within the past 30 years. Such sources are used extensively to measure instantaneously, simultaneously and nondestruclively, the major, minor and trace elements in different materials. The low residual activity, bulk sample analysis and high accuracy for short lived elements are improved. Also, the portable isotopic neutron sources, offer a wide range of industrial and field applications. In this talk, a review on the theoretical basis and design considerations of different facilities using several isotopic neutron sources for elemental analysis of different materials is given. INTRODUCTION In principle there are two ways to use neutrons for elemental and isotopic abundance analysis in samples. One is the neutron activation analysis which we call it the "off-line" where the neutron - induced radioactivity is observed after the end of irradiation. The other one we call it the "on-line" where the capture gamma-rays is observed during the neutron bombardment. Actually, the sequence of events occurring during the most common type of nuclear reaction used in this analysis namely the neutron capture or (n, gamma) reaction, is well known for the people working in this field. The neutron interacts with the target nucleus via a non-elastic collision, a compound nucleus forms in an excited state.
    [Show full text]
  • Of the Periodic Table
    of the Periodic Table teacher notes Give your students a visual introduction to the families of the periodic table! This product includes eight mini- posters, one for each of the element families on the main group of the periodic table: Alkali Metals, Alkaline Earth Metals, Boron/Aluminum Group (Icosagens), Carbon Group (Crystallogens), Nitrogen Group (Pnictogens), Oxygen Group (Chalcogens), Halogens, and Noble Gases. The mini-posters give overview information about the family as well as a visual of where on the periodic table the family is located and a diagram of an atom of that family highlighting the number of valence electrons. Also included is the student packet, which is broken into the eight families and asks for specific information that students will find on the mini-posters. The students are also directed to color each family with a specific color on the blank graphic organizer at the end of their packet and they go to the fantastic interactive table at www.periodictable.com to learn even more about the elements in each family. Furthermore, there is a section for students to conduct their own research on the element of hydrogen, which does not belong to a family. When I use this activity, I print two of each mini-poster in color (pages 8 through 15 of this file), laminate them, and lay them on a big table. I have students work in partners to read about each family, one at a time, and complete that section of the student packet (pages 16 through 21 of this file). When they finish, they bring the mini-poster back to the table for another group to use.
    [Show full text]
  • PGNAA Neutron Source Moderation Setup Optimization
    Submitted to ‘Chinese Physics C PGNAA neutron source moderation setup optimization Zhang Jinzhao1（张金钊）Tuo Xianguo1（庹先国） (1.Chengdu University of Technology Applied Nuclear Techniques in Geoscience Key Laboratory of Sichuan Province，Chengdu 610059，China) Abstract: Monte Carlo simulations were carried out to design a prompt γ-ray neutron activation analysis (PGNAA) thermal neutron output setup using MCNP5 computer code. In these simulations the moderator materials, reflective materials and structure of the PGNAA 252Cf neutrons of thermal neutron output setup were optimized. Results of the calcuations revealed that the thin layer paraffin and the thick layer of heavy water moderated effect is best for 252Cf neutrons spectrum. The new design compared with the conventional neutron source design, the thermal neutron flux and rate were increased by 3.02 times and 3.27 times. Results indicate that the use of this design should increase the neutron flux of prompt gamma-ray neutron activation analysis significantly. Key word: PGNAA; neutron source; thermal neutron; moderation; reflection 1. Introduction study, Monte Carlo calculation was carried out for the Prompt gamma ray neutron activation analysis design of a 252Cf neutron source moderation setup for the (PGNAA) is a rapid, nondestructive, powerful analysis cement samples[7]. The model of Monte Carlo multielemental analysis technique, large samples of some simulation was verified by experiment[8, 9].We improve minor, trace light elements and is used in industrial the thermal neutron source yield rate of 252Cf neutron by control[1-5]. In a PGNAA analysis, the sample nuclear the PGNAA neutron source structure to the design. The composition is determined from prompt gamma rays calculation results for the new design were compared which produced through neutron inelastic scattering and with the previous, example: themal neutron flux rate, fast thermal neutron capture.
    [Show full text]
  • Arxiv:1506.05417V2 [Physics.Ins-Det] 28 Jul 2016
    http://dx.doi.org/10.1016/j.apradiso.2016.06.032 A precise method to determine the activity of a weak neutron source using a germanium detector M. J. M. Dukea, A. L. Hallinb, C. B. Kraussb, P. Mekarskib,∗, L. Sibleyb aSLOWPOKE Nuclear Reactor Facility, University of Alberta, Edmonton, AB T6G 2G7, Canada bDepartment of Physics, University of Alberta, Edmonton, AB T6G 2E1, Canada Abstract A standard high purity germanium (HPGe) detector was used to determine the previously unknown neutron activity of a weak americium-beryllium (AmBe) neutron source. γ rays were created through 27Al(n,n0), 27Al(n,γ) and 1H(n,γ) reactions induced by the neutrons on aluminum and acrylic disks, respectively. These γ rays were measured using the HPGe detector. Given the unorthodox experimental arrangement, a Monte Carlo simulation was developed to model the efficiency of the detector system to determine the neutron activity from the measured γ rays. The activity of our neutron source was determined to be 307.4 ± 5.0 n/s and is consistent for the different neutron-induced γ rays. Keywords: neutron activation, germanium detector, simulation, spectroscopy, activity determination 1. Introduction As neutrons are difficult to detect, determining the absolute activity of a neutron source is challenging. This difficulty increases as the activity of the source decreases. Sophisticated techniques exist for neutron activity measure- ments, including the manganese bath technique[1], proton recoil techniques[2] and the use of 3He proportional counters[3]; nevertheless, the development of a method utilizing commonly available high purity germanium (HPGe) detectors would be advantageous. HPGe's are an industry standard for measuring γ ray energies to high preci- sion.
    [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]
  • Beryllium Compounds (A) BERYLLIUM COMPOUNDS
    Beryllium Compounds (A) BERYLLIUM COMPOUNDS 107-02-8 Hazard Summary Inhalation exposure to beryllium primarily occurs in the workplaces where it is mined, processed, or converted into alloys and chemicals, or from the burning of coal or fuel oil and in tobacco smoke. Acute (short-term) inhalation exposure to high levels of beryllium has been observed to cause inflammation of the lungs or acute pneumonitis (reddening and swelling of the lungs) in humans; after exposure ends, these symptoms may be reversible. Chronic (long-term) inhalation exposure of humans to beryllium has been reported to cause chronic beryllium disease (berylliosis), in which granulomatous lesions (noncancerous) develop in the lung. Human epidemiology studies are limited, but suggest a causal relationship between beryllium exposure and an increased risk of lung cancer. Inhalation exposure to beryllium has been demonstrated to cause lung cancer in rats and monkeys. EPA has classified beryllium as a Group B1, probable human carcinogen. Please Note: The main sources of information for this fact sheet are EPA's Integrated Risk Information System (IRIS) (3), which contains information on oral chronic toxicity and the RfD and inhalation chronic toxicity and the RfC, and the carcinogenic effects of beryllium including the unit cancer risk for inhalation exposure, EPA's Toxicological Review of Beryllium and Compounds (2), and the Agency for Toxic Substances and Disease Registry's (ATSDR's) Toxicological Profile for Beryllium. (1) Uses Pure beryllium and its metal alloys have applications in electrical components, tools, structural components for aircraft, missiles, and satellites, and other metal-fabricating uses. (1) Beryllium is also used in consumer products, such as televisions, calculators, and personal computers.
    [Show full text]