An Introduction to Neutron Scattering - Spallation Neutron Source

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By “Tilting” the Precession-Field Region, Spin Precession Can Be Used to Code a Specific Component of the Neutron Wavevector If a neutron passes through a rectangular field region at an angle, its total precession phase will depend only on k⊥ . ω L = γB φ = ω t L = γB d = vsin χ KBd k with K = 0.291 (Gauss.cm.Å) -1 ⊥ d B χ k // Stop precession here Start precession here k k ⊥
“Phonon Focusing” • For a single incident neutron wavevector, k I , neutrons are scattered to k F by a phonon of frequency ω o and to k f by neighboring phonons lying on the “scattering surface”. – The topology of the scattering surface is related to that of the phonon dispersion surface and it is locally flat • Provided the edges of the NSE precession field region are parallel to the scattering surface, all neutrons with scattering wavevectors on the scattering surface will have equal spin-echo phase k I Q 0 k F k f k f⊥ scattering surface Precession field region
Page 1 and 2:
y Roger Pynn Los Alamos National La
Page 3 and 4:
Why do Neutron Scattering? • To d
Page 5 and 6:
The Neutron has Both Particle-Like
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Thermal Neutrons, 8 keV X-Rays & Lo
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Brightness & Fluxes for Neutron & X
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Scattering by a Single (fixed) Nucl
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Coherent and Incoherent Scattering
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so or ie Coherent Elastic Scatterin
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Neutrons can also gain or lose ener
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Magnetic Scattering • The magneti
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Ene rgy Trans fe r (me V) 10000 100
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References • Introduction to the
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Overview 1. Essential messages from
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What Do We Need to Do a Basic Neutr
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About 1.5 Useful Neutrons Are Produ
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The ESRF* & ILL* With Grenoble & th
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Neutron Sources Provide Neutrons fo
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Proton Radiography 800-MeV Linear A
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Components of a Spallation Source A
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Simultaneously Using Neutrons With
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The Actual ToF Gain From Source Pul
Page 43 and 44:
Why Isn’t There a Universal Neutr
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• Uncertainties in the neutron wa
Page 47 and 48:
Typical Neutron Scattering Instrume
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Most Neutron Detectors Use 3 He •
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Rotating Choppers Are Used to Tailo
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3. Diffraction Next Lecture 1. Diff
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2. Diffraction This Lecture 1. Diff
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Neutron Diffraction • Neutron dif
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For Periodic Arrays of Nuclei, Cohe
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We would be better off if diffracti
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Powder - A Polycrystalline Mass All
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Measuring Neutron Diffraction Patte
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Time-of-Flight Powder Diffraction U
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There’s more than meets the eye i
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How good is this function? Protein
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High-resolution Neutron Powder Diff
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Texture Measurement by Diffraction
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Definitions of Stress and Strain
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Why use Metal Matrix Composites ? F
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Neutron Diffraction Measures Mean R
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Deformation Mechanism in U/Nb Alloy
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Obtaining the Pair Distribution Fun
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Effect of Doping on the Octahedra
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Surface Reflection Is Very Differen
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What Is the Neutron Wavevector Insi
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Only Those Thermal or Cold Neutrons
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What do the Amplitudes a R and a T
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Fresnel’s Law for a Thin Film •
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Reflection by a Graded Interface io
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Direct Inversion of Reflectivity Da
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4 R*Q z 10 -7 10 -8 10 -9 1.3% PEG
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Polarized Neutron Reflectometry (PN
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Reflection from Rough Surfaces z z
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fi fi fi Q =kf -ki Qx-Qz Transforma
Page 111 and 112:
Observation of Hexagonal Packing of
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This Lecture 5. Small Angle Neutron
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Two Views of the Components of a Ty
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Where Does SANS Fit As a Structural
Page 119 and 120:
Instrumental Resolution for SANS Tr
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SANS Measures Particle Shapes and I
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Examples of Spherically-Averaged Fo
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Correlations Can Be Measured in Con
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Radius of Gyration Is the Particle
Page 129 and 130:
Contrast & Contrast Matching Water
Page 131 and 132: Verification of of the Gaussian Coi
Page 133 and 134: Porod Scattering function. n correl
Page 135 and 136: ln(I) Typical Intensity Plot for SA
Page 137 and 138: References • Viewgraphs describin
Page 139 and 140: We Have Seen How Neutron Scattering
Page 141 and 142: The Elastic & Inelastic Scattering
Page 143 and 144: Examples of S(Q,ω) and S s(Q,ω)
Page 145 and 146: Inelastic Magnetic Scattering of Ne
Page 147 and 148: Measured Inelastic Neutron Scatteri
Page 149 and 150: Atomic Motions for Longitudinal & T
Page 151 and 152: Phonons - the Classical Use for Ine
Page 153 and 154: The Accessible Energy and Wavevecto
Page 155 and 156: What Use Have Phonon Measurements B
Page 157 and 158: Time-of-flight Methods Can Give Com
Page 159 and 160: Neutron Spin Echo By Roger Pynn* Lo
Page 161 and 162: • Uncertainties in the neutron wa
Page 163 and 164: The Underlying Physics of Neutron S
Page 165 and 166: How does a Neutron Spin Behave when
Page 167 and 168: The Principles of NSE are Very Simp
Page 169 and 170: For Quasi-elastic Scattering, the E
Page 171 and 172: Neutron counts ( per 50 sec) Neutro
Page 173 and 174: Field-Integral Inhomogeneities caus
Page 175 and 176: Neutron Spin Echo study of Deformat
Page 177 and 178: Neutron Spin Phases NRSE spectromet
Page 179 and 180: The Measured Polarization for NRSE
Page 181: Measuring Line Shapes for Inelastic
Page 185 and 186: An NRSE Triple Axis Spectrometer at
Page 187 and 188: “Tilted” Fields for Diffraction
Page 189 and 190: Spin Echo SANS using Magnetic Films
Page 191: Conclusion: NSE Provides a Way to S
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An Introduction to Neutron Scattering - Spallation Neutron Source

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