Neutron Scattering Facilities in Europe Present Status and Future Perspectives
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The Theoretical Foundation of Spin-Echo Small-Angle Neutron
The Theoretical Foundation of Spin‐Echo Small‐Angle Neutron Scattering (SESANS) Applied in Colloidal System Wei‐Ren Chen, Gregory S. Smith, and Kenneth W. Herwig (NSSD ORNL) Yun Liu (NCNR NIST & Chemistry, University of Delaware) Li (Emily) Liu (Nuclear Engineering, RPI) Xin Li, Roger Pynn (Physics, Indiana University) Chwen‐Yang Shew (Chemistry, CUNY) UCANS‐II Indiana University July 08th 2011 Bloomington, IN Outline 1. Motivation — why Spin-Echo Small-Angle Neutron Scattering (SESANS)? 2. Basic Theory — what does SESANS measure? 3. Results and Discussions — what can SESANS do? (1). Straightforward observation of potential (2). Sensitivity to the local structure (3). Sensitivity to the structural heterogeneity 4. Summary Outline 1. Motivation — why Spin-Echo Small-Angle Neutron Scattering (SESANS)? 2. Basic Theory — what does SESANS measure? 3. Results and Discussions — what can SESANS do? (1). Straightforward observation of potential (2). Sensitivity to the local structure (3). Sensitivity to the structural heterogeneity 4. Summary Neutron Scattering Structure (Elastic Scatt.) Dynamics (Inelastic Scatt.) Small‐Angle Neutron Quasi‐Elastic Neutron Unpolarized Scattering (SANS), Scattering (QENS), beam Neutron Diffraction, Inelastic Neutron Scattering Neutron Reflectometry (INS) Polarized Spin‐Echo Small‐Angle Neutron Spin‐Echo (NSE) beam Neutron Scattering (SESANS) Neutron Scattering Structure (Elastic Scatt.) Dynamics (Inelastic Scatt.) Small‐Angle Neutron Quasi‐Elastic Neutron Unpolarized Scattering (SANS), Scattering (QENS), beam Neutron -
Neutron Scattering
Neutron Scattering John R.D. Copley Summer School on Methods and Applications of High Resolution Neutron Spectroscopy and Small Angle Neutron Scattering NIST Center for NeutronNCNR Summer Research, School 2011 June 12-16, 2011 Acknowledgements National Science Foundation NIST Center for Neutron (grant # DMR-0944772) Research (NCNR) Center for High Resolution Neutron Scattering (CHRNS) 2 NCNR Summer School 2011 (Slow) neutron interactions Scattering plus Absorption Total =+Elastic Inelastic scattering scattering scattering (diffraction) (spectroscopy) includes “Quasielastic neutron Structure Dynamics scattering” (QENS) NCNR Summer School 2011 3 Total, elastic, and inelastic scattering Incident energy Ei E= Ei -Ef Scattered energy Ef (“energy transfer”) Total scattering: Elastic scattering: E = E (i.e., E = 0) all Ef (i.e., all E) f i Inelastic scattering: E ≠ E (i.e., E ≠ 0) D f i A M M Ef Ei S Ei D S Diffractometer Spectrometer (Some write E = Ef –Ei) NCNR Summer School 2011 4 Kinematics mv= = k 1 222 Emvk2m==2 = Scattered wave (m is neutron’s mass) vector k , energy E 2θ f f Incident wave vector ki, energy Ei N.B. The symbol for scattering angle in Q is wave vector transfer, SANS experiments is or “scattering vector” Q =Q is momentum transfer θ, not 2θ. Q = ki - kf (For x-rays, Eck = = ) (“wave vector transfer”) NCNR Summer School 2011 5 Elastic scattering Q = ki - kf G In real space k In reciprocal space f G G G kf Q ki 2θ 2θ G G k Q i E== 0 kif k Q =θ 2k i sin NCNR Summer School 2011 6 Total scattering, inelastic scattering Q = ki - kf G kf G Q Qkk2kkcos2222= +− θ 2θ G if if ki At fixed scattering angle 2θ, the magnitude (and the direction) of Q varies with the energy transfer E. -
NEUTRON ELECTRIC-DIPOLE MOMENT, ULTRACOLD NEUTRONS and POLARIZED 3He
NEUTRON ELECTRIC-DIPOLE MOMENT, ULTRACOLD NEUTRONS AND POLARIZED 3He R. GOLUB~and Steve K. LAMOREAUXb aHahfl_Mejtfler Institut, Postfach 390128, Glienicker Strasse 100, 14109 Berlin, Germany b University of Washington, Department of Physics FM-15, Seattle, WA 98195, USA NORTH-HOLLAND PHYSICS REPORTS (Review Section of Physics Letters) 237, No. 1(1994)1—62. PHYSICS REPORTS North-Holland Neutron electric-dipole moment, ultracold neutrons and polarized 3He R. Goluba and Steve K. Lamoreauxb aHahnMeitner Institut, Postfach 390128, Glienicker Strasse 100, 14109 Berlin, Germany buniversily of Washington, Department of Physics FM-15, Seattle, WA 98195, USA Received May 1993; editor: J. Eichler Contents: 1. Introduction 4 5.3. Solution by use of the secular approximation 38 1.1. Historical background 4 5.4. Elimination of the pseudomagnetic field 2. Current experimental technique 8 suppression by feedback to w~ 39 2.1. Ultracold neutrons (UCN) 8 5.5. Effects of the z component of the pseudomagnetic 2.2. Neutron EDM measurements with stored UCN 10 field 42 2.3. Recent EDM experiments using UCN 13 5,6. Effects of offsets in the first-harmonic signal 44 3. Superfluid He neutron EDM with 3He 6. Noise analysis 45 comagnetometer 19 6.1. Model of the system for noise analysis 45 3.1. Introduction 19 6.2. Initial polarization and UCN density 45 3.2. Production of UCN in superfluid 4He 20 6.3. Analysis of harmonically modulated dressing 46 3.3. Polarization of UCN 21 6.4. Evolution of the UCN polarization and density 3.4. Polarization of 3He 22 under modulated dressing 46 3.5. -
Optimizing Crystal Volume for Neutron Diffraction: D-Xylose Isomerase
Eur Biophys J (2006) 35:621–632 DOI 10.1007/s00249-006-0068-4 ARTICLE Optimizing crystal volume for neutron diffraction: D-xylose isomerase Edward H. Snell Æ Mark J. van der Woerd Æ Michael Damon Æ Russell A. Judge Æ Dean A. A. Myles Æ Flora Meilleur Received: 15 February 2006 / Revised: 27 March 2006 / Accepted: 4 April 2006 / Published online: 25 May 2006 Ó EBSA 2006 Abstract Neutron diffraction is uniquely sensitive to studies for a larger number of samples that require hydrogen positions and protonation state. In that information on hydrogen position and/or protonation context structural information from neutron data is state. complementary to that provided through X-ray dif- fraction. However, there are practical obstacles to overcome in fully exploiting the potential of neutron diffraction, i.e. low flux and weak scattering. Several approaches are available to overcome these obstacles Introduction and we have investigated the simplest: increasing the diffracting volume of the crystals. Volume is a quan- Neutron diffraction tifiable metric that is well suited for experimental de- sign and optimization techniques. By using response X-ray structural crystallography is a powerful tech- surface methods we have optimized the xylose isom- nique to visualize the machinery of life on a molecular erase crystal volume, enabling neutron diffraction scale. However, hydrogen atoms are not usually seen while we determined the crystallization parameters because X-ray scattering from hydrogen atoms is weak with a minimum of experiments. Our results suggest a compared to other atoms. Knowledge of the location of systematic means of enabling neutron diffraction hydrogen atoms and water molecules is often necessary to completely understand the reaction mechanisms, pathways and structure–function relationships. -
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. -
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. -
Small Angle Scattering in Neutron Imaging—A Review
Journal of Imaging Review Small Angle Scattering in Neutron Imaging—A Review Markus Strobl 1,2,*,†, Ralph P. Harti 1,†, Christian Grünzweig 1,†, Robin Woracek 3,† and Jeroen Plomp 4,† 1 Paul Scherrer Institut, PSI Aarebrücke, 5232 Villigen, Switzerland; [email protected] (R.P.H.); [email protected] (C.G.) 2 Niels Bohr Institute, University of Copenhagen, Copenhagen 1165, Denmark 3 European Spallation Source ERIC, 225 92 Lund, Sweden; [email protected] 4 Department of Radiation Science and Technology, Technical University Delft, 2628 Delft, The Netherlands; [email protected] * Correspondence: [email protected]; Tel.: +41-56-310-5941 † These authors contributed equally to this work. Received: 6 November 2017; Accepted: 8 December 2017; Published: 13 December 2017 Abstract: Conventional neutron imaging utilizes the beam attenuation caused by scattering and absorption through the materials constituting an object in order to investigate its macroscopic inner structure. Small angle scattering has basically no impact on such images under the geometrical conditions applied. Nevertheless, in recent years different experimental methods have been developed in neutron imaging, which enable to not only generate contrast based on neutrons scattered to very small angles, but to map and quantify small angle scattering with the spatial resolution of neutron imaging. This enables neutron imaging to access length scales which are not directly resolved in real space and to investigate bulk structures and processes spanning multiple length scales from centimeters to tens of nanometers. Keywords: neutron imaging; neutron scattering; small angle scattering; dark-field imaging 1. Introduction The largest and maybe also broadest length scales that are probed with neutrons are the domains of small angle neutron scattering (SANS) and imaging. -
Single Crystal Diffuse Neutron Scattering
Review Single Crystal Diffuse Neutron Scattering Richard Welberry 1,* ID and Ross Whitfield 2 ID 1 Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia 2 Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA; whitfi[email protected] * Correspondence: [email protected]; Tel.: +61-2-6125-4122 Received: 30 November 2017; Accepted: 8 January 2018; Published: 11 January 2018 Abstract: Diffuse neutron scattering has become a valuable tool for investigating local structure in materials ranging from organic molecular crystals containing only light atoms to piezo-ceramics that frequently contain heavy elements. Although neutron sources will never be able to compete with X-rays in terms of the available flux the special properties of neutrons, viz. the ability to explore inelastic scattering events, the fact that scattering lengths do not vary systematically with atomic number and their ability to scatter from magnetic moments, provides strong motivation for developing neutron diffuse scattering methods. In this paper, we compare three different instruments that have been used by us to collect neutron diffuse scattering data. Two of these are on a spallation source and one on a reactor source. Keywords: single crystal; diffuse scattering; neutrons; spallation source; time-of-flight 1. Introduction Bragg scattering, which is used in conventional crystallography, gives only information about the average crystal structure. Diffuse scattering from single crystals, on the other hand, is a prime source of local structural information. There is now a wealth of evidence to show that the more local structure is investigated the more we are obliged to reassess our understanding of crystalline structure and behaviour [1]. -
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 -
Determination of Uranium and Thorium by Neutron Activation Analysis Applied to Fossil Samples Dating
2011 International Nuclear Atlantic Conference - INAC 2011 Belo Horizonte,MG, Brazil, October 24-28, 2011 ASSOCIAÇÃO BRASILEIRA DE ENERGIA NUCLEAR - ABEN ISBN: 978-85-99141-04-5 DETERMINATION OF URANIUM AND THORIUM BY NEUTRON ACTIVATION ANALYSIS APPLIED TO FOSSIL SAMPLES DATING Regina B. Ticianelli 1, Ana Maria Graciano Figueiredo 1, Guilherme S. Zahn 1, 2,3 2 Angela Kinoshita , Oswaldo Baffa 1 Instituto de Pesquisas Energéticas e Nucleares –IPEN-CNEN/SP, C.P. 11049, 05422-970, São Paulo, SP. [email protected] 2 Departamento de Física, FFCRLP- USP, Ribeirão Preto, SP 3 Universidade Sagrado Coração, Bauru, SP ABSTRACT Electron Spin Resonance (ESR) dating is based on the fact that ionizing radiation can create stable free radicals in insulating materials, like tooth enamel and bones. The concentration of these radicals - determined by ESR - is a function of the dose deposed in the sample along the years. The accumulated dose of radiation, called Archeological Dose, is produced by the exposition to environmental radiation provided by U, Th, K and cosmic rays. If the environmental dose rate in the site where the fossil sample is found is known, it is possible to convert this dose into the age of the sample. The annual dose rate coming from the radioactive elements present in the soil and in the sample itself can be calculated by determining the U, Th and K concentration. Therefore, the determination of the dose rate depends on the concentration of these main radioactive elements. Neutron Activation Analysis has the sensitivity and the accuracy necessary to determine U, Th and K with this objective. -
Opportunities and Challenges in Neutron Crystallography
EPJ Web of Conferences 236, 02001 (2020) https://doi.org/10.1051/epjconf/202023602001 JDN 24 Opportunities and challenges in neutron crystallography Nathan Richard Zaccai1,*, and Nicolas Coquelle2,† 1CIMR, University of Cambridge, Cambridge CB2 0XY, United Kingdom 2Institut Laue Langevin, 38042 Grenoble Cedex 9, France Abstract. Neutron and X-ray crystallography are complementary to each other. While X-ray scattering is directly proportional to the number of electrons of an atom, neutrons interact with the atomic nuclei themselves. Neutron crystallography therefore provides an excellent alternative in determining the positions of hydrogens in a biological molecule. In particular, since highly polarized hydrogen atoms (H+) do not have electrons, they cannot be observed by X-rays. Neutron crystallography has its own limitations, mainly due to inherent low flux of neutrons sources, and as a consequence, the need for much larger crystals and for different data collection and analysis strategies. These technical challenges can however be overcome to yield crucial structural insights about protonation states in enzyme catalysis, ligand recognition, as well as the presence of unusual hydrogen bonds in proteins. 1 Introduction Although X-ray crystallography has become the workhorse of structural biology, Neutron crystallography has several advantages to offer in the structural analysis of biological molecules. X-rays and neutrons interact differently with matter in general, and with biological macromolecules in particular. These two crystallography approaches are therefore complementary to each other [1]. While X-ray scattering is directly proportional to the number of electrons of an atom, neutrons interact with the atomic nuclei themselves. In this perspective, hydrogen atoms, which represent ~50% of the atomistic composition of proteins and DNA, are hardly visible using X-ray crystallography, while they can be observed in nuclear density maps derived from neutron diffraction data even at moderate resolution (2.5Å and higher). -
LENS Report Low Energy Accelerator-Driven Neutron Sources
LENS Report Low Energy Accelerator-driven Neutron Sources LENS Ad-hoc Working Group CANS Nov. 2020 2 www.lens-initiative.org Table of Content 1 Foreword ................................................................................................................................6 2 Executive summary .................................................................................................................8 3 Neutrons for science and industry ......................................................................................... 12 4 Neutron production and landscape of neutron Infrastructures in Europe .............................. 16 4.1 Neutron production ........................................................................................................... 16 4.2 Situation in Europe ............................................................................................................ 16 4.3 Situation outside Europe ................................................................................................... 18 5 Capabilities of CANS .............................................................................................................. 22 5.1 What is a CANS ? ............................................................................................................... 22 5.2 What are the different types of facilities that can be considered? ...................................... 22 5.3 What performances can be achieved on a CANS for neutron scattering ............................. 23 6 Advantages / limitations