1. SNS Experimental FacilitiesOak Ridge X0000910/arb Neutron Instruments for Materials Research T.E. Mason Experimental Facilities Division Spallation Neutron Source Acknowledgements: Doug Abernathy, John Ankner, Ken Herwig, Frank Klose, Jinkui Zhao, Xun-Li Wang

2. SNS Experimental FacilitiesOak Ridge X0000910/arb 2 A Brief Aside on What You Actually Measure: 98-6249 uc/rra

3. SNS Experimental FacilitiesOak Ridge X0000910/arb 3 Neutron Scattering Cross-Section 98-6250 uc/rra

4. SNS Experimental FacilitiesOak Ridge X0000910/arb 4 CW vs Pulsed Instrumentation In general continuous sources work with fixed wavelengths ( , all t) and pulsed sources work with a wavelength band (  t, all – using time and distance to determine velocities and hence wavelengths) If the useful wavelength band is dispersed over the full time between pulses then the pulsed instrument counts useful neutrons all of the time and the figure of merit is the peak flux If the full time between pulses is not useful then the figure of merit is reduced by the duty cycle For fixed wavelengths, counting continuously the integrated flux is the figure of merit Variations (e.g. pulsed instrument at CW source) can, and do exist

5. SNS Experimental FacilitiesOak Ridge X0000910/arb 5 Example – Reactor - SANS As an example consider the static approximation in a homogeneous system: Fourier transform of scattering length density for an object 98-6259 uc/rra

6. SNS Experimental FacilitiesOak Ridge X0000910/arb 6 cAMP-Dependent Protein Kinase (PKA) Combining Neutrons with X-rays PKA catalyzes a variety of cellular activities, ranging from gene induction to color change in pigment cells. PKA serves as the prototype for a class of enzymes which catalyzes protein phosphorylation, the major mechanism of cellular regulation. The combination of neutron studies and x-ray structures of PKA subunits has provided insights into the quaternary structure of PKA, which is key to the understanding of PKA function.

7. SNS Experimental FacilitiesOak Ridge X0000910/arb 7 RC with deuterated R-subunit PKA (R2C2) with deuterated R- subunits Free C and Truncated R with x-ray Neutron Contrast Data of PKA and RC

8. SNS Experimental FacilitiesOak Ridge X0000910/arb 8 Momentum Resolution 98-6252 uc/trh

9. SNS Experimental FacilitiesOak Ridge X0000910/arb 9 Having Made Some Neutrons We Want A Monochromatic Beam! 98-6253 uc/trh

10. SNS Experimental FacilitiesOak Ridge X0000910/arb 10 Pinhole SANS NIST/NSF 30 m SANS NG-3 cold neutron guide 20 MW reactor, hydrogen cold source

11. SNS Experimental FacilitiesOak Ridge X0000910/arb 11 NIST SANS Characteristics and Performance Source: neutron guide (NG-3), 60 mm x 60 mm Monochromator: mechanical velocity selector with variable speed and pitch Wavelength Range: 0.5 nm-2.0 nm Wavelength Resolution: 9%-30% (FWHM) Source-to-Sample Dist.: 4 m to 16 m in steps via insertion of neutron guide sections Sample-to-Detector Dist.: 1.3 m to 13 m Collimation: circular pinhole collimation Sample Size: 0 to 25 mm diam Q-Range: 0.015 nm-1 to 6 nm-1 Detector: 650 mm x 650 mm 3 He position-sensitive proportional counter (10mm resol.)

12. SNS Experimental FacilitiesOak Ridge X0000910/arb 12 excitations characterized by  ´´(Q,  )  a measure of absorption at (Q,  ). neutron scattering measures: S(Q,  ) ~  ´´(Q,  ) [n(  )+1]. note: Q  0, recover uniform susceptibility. the proportionality constant involves magnetic moment direction and form factor. Neutron Scattering and Spin Fluctuations

13. SNS Experimental FacilitiesOak Ridge X0000910/arb 13  o (Q,  ) for Metals Excitations are electron-hole pairs Lindhard susceptibility: As T  0 states near  F dominate Note: NMR relaxation rate:

14. SNS Experimental FacilitiesOak Ridge X0000910/arb 14 Normal State Energy Dependence As the frequency is increased the peaks become less well defined. The response is qualitatively quite similar to that of the spin density wave system Cr, above T N.

15. SNS Experimental FacilitiesOak Ridge X0000910/arb 15 Example – Reactor –Triple Axis RITA (Re-Invented Triple Axis) at Risø, DR-3 Denmark 10 MW reactor, supercritical hydrogen cold source

16. SNS Experimental FacilitiesOak Ridge X0000910/arb 16 Having Made Some Neutrons We Want A Monochromatic Beam! 98-6254 uc/trh

17. SNS Experimental FacilitiesOak Ridge X0000910/arb 17 For Inelastic Scattering You Also Need Energy Analysis 98-6256 uc/rra

18. SNS Experimental FacilitiesOak Ridge X0000910/arb 18 Crystal Monochromator (continued) 98-6255 uc/trh

19. SNS Experimental FacilitiesOak Ridge X0000910/arb 19 Triple-Axis Spectrometer Resolution There are analytical methods for calculating the resolution (Cooper + Nathans, Nielsen + Bjerrum-Møller, Popovici) These are obtained from the program RESCAL for collimation 60'– 60'– 60' – 60' 30' PG002monochromator and analyzer 10' sample mosaic E f = 5meV ( = 4.04 Å) h  = 0 q = 1 Å -1 98-6258 uc/rra

20. SNS Experimental FacilitiesOak Ridge X0000910/arb 20 Incident Beam Optics Supermirror guide in front of the monochromator increases flux Sapphire filter reduces gamma and fast neutron background and protects guide Velocity selector in front of monochromator remove higher order

21. SNS Experimental FacilitiesOak Ridge X0000910/arb 21 Effect of the Guide

22. SNS Experimental FacilitiesOak Ridge X0000910/arb 22 Secondary Spectrometer Area detector and analyser crystal array permits flexible focussing

23. SNS Experimental FacilitiesOak Ridge X0000910/arb 23 SPINS at NIST A similar (on the back end) instrument is SPINS at NIST

24. SNS Experimental FacilitiesOak Ridge X0000910/arb 24 Time-of-Flight Inelastic Instruments Two basic types – direct geometry – fixed E i (e.g. HET chopper) – Indirect geometry – fixed E f (e.g. IRIS backscattering)

25. SNS Experimental FacilitiesOak Ridge X0000910/arb 25 Chopper Spectrometers Operate in the thermal to epithermal energy range – 5 meV < E i < 1000 meV Use fast, magnetic bearing Fermi choppers to select E i Maximal Q range with continuous coverage to large scattering angles – Need room at least on one side for scattering chamber Consider two choppers should be placed on the bottom upstream moderator at end positions - BL9 & BL18 at SNS

26. SNS Experimental FacilitiesOak Ridge X0000910/arb 26 Target Layout X = 5 m X = 6.5 m BL18 BL17 BL9

27. SNS Experimental FacilitiesOak Ridge X0000910/arb 27 Geometric constraints X mm 22 LiLi LfLf BL18: X = 5 m  m = 35° For 2  >125° & L f = 2.5 m, L i =13.0 m For 2  = 60° & L f = 6.0 m, L i =13.1 m BL9: X = 6.5 m  m = 35° For 2  >125° & L f = 2.5 m, L i =15.7 m For 2  = 60° & L f = 6.0 m, L i =15.8 m Accessible regions in L f lie below a straight line in (L i,L f ) plane

28. SNS Experimental FacilitiesOak Ridge X0000910/arb 28 Flux on sample at 200meV - 5% elastic resolution Optimum flux not accessible for any L 3

29. SNS Experimental FacilitiesOak Ridge X0000910/arb 29 Flux on sample at 200meV - 1% elastic resolution Can optimize flux for a given L 3 that is not too large

30. SNS Experimental FacilitiesOak Ridge X0000910/arb 30 Proposed two spectrometer layout T0 E0 Pit Area Sample Beamstop Detectors BL17 - “high resolution” BL18 - “high flux”

33. SNS Experimental FacilitiesOak Ridge X0000910/arb 33 Instrument parameters

34. SNS Experimental FacilitiesOak Ridge X0000910/arb 34 Instrument parameters

35. SNS Experimental FacilitiesOak Ridge X0000910/arb 35 Resolution and flux calculations

36. SNS Experimental FacilitiesOak Ridge X0000910/arb 36 Resolution and flux calculations

37. SNS Experimental FacilitiesOak Ridge X0000910/arb 37 Q-  space accessible with proposed spectrometers

38. SNS Experimental FacilitiesOak Ridge X0000910/arb 38 Comparison to current chopper spectrometers

39. SNS Experimental FacilitiesOak Ridge X0000910/arb 39 High Resolution Backscattering Spectrometer Performance gains over comparable reactor backscattering instruments >100 (depending on bandwidth needed) High-Q option (with Si 311) 500x IN13 and 18x IRIS (with 3 times Q range and better resolution!) Crystal analyzer (Si) with 84 m incident flight path Achieves 2.2  eV resolution at the elastic position with 250  eV bandwidth Can operate up to 18 meV energy transfer with 10  eV resolution Unprecedented capabilities 2000-03452/arb

40. SNS Experimental FacilitiesOak Ridge X0000910/arb 40 Instrument Resolution and Q-  Range Elastic Resolution 2.2  eV (fwhm)

41. SNS Experimental FacilitiesOak Ridge X0000910/arb 41 supermirror funnel detector for top analyzer detector for bottom analyzer beam stop top analyzer bottom analyzer evacuated sample chamber scattering vessel Scattering Chamber

42. SNS Experimental FacilitiesOak Ridge X0000910/arb 42 Guide Design 84 m total flight path moderator face to sample Curved guide – radius of curvature 4.325 km – 10 cm horizontal x 12 cm vertical – Natural Ni (outer radius horizontal needs higher index) – begins 1 m from moderator face Supermirror funnel, ends 30 cm from sample – horizontal, 3 x  c for Ni, 10 cm to 3 cm over 5 m – vertical, 4 x  c for Ni, 12 cm to 3 cm over 6 m Gains – 1200;  = 6.3 Å – 400;  = 3.2 Å

43. SNS Experimental FacilitiesOak Ridge X0000910/arb 43 39 Shutter and Core Insert Regions for the Standard Shutters

44. SNS Experimental FacilitiesOak Ridge X0000910/arb 44 Major Spectrometer Components Source/Moderator decoupled, supercritical poisoned H 2, TU Incident flight path - 84 m moderator face to sample position Chopper System - 3 bandwidth/frame overlap choppers Sample - dimensions 3 x 3 cm 2 Analyzer crystals, Bragg angle = 88 deg – Si (111): = 6.267 Å, 2.9 ster, 26 m 2,  d/d ~ 3.5 10 -4 – Si (311): = 3.273 Å, 1.45 ster, 13 m 2,  d/d ~ 4.0 10 -4 Final flight path - 3 m sample-analyzer, 2.5 m analyzer-detector Detectors – Backscattering for diffraction – ~ 7040 cm 2 PSD 1 x 1 cm 2 spatial resolution

45. SNS Experimental FacilitiesOak Ridge X0000910/arb 45 Melittin in Alkanethiol/Phospholipid Hybrid Bilayer Membranes - NIST

46. SNS Experimental FacilitiesOak Ridge X0000910/arb 46 Melittin in Alkanethiol/Phospholipid Hybrid Bilayer Membranes - NIST

47. SNS Experimental FacilitiesOak Ridge X0000910/arb 47 NG1 Reflectometer: Polarized Beam - NIST

48. SNS Experimental FacilitiesOak Ridge X0000910/arb 48 MBE Chamber for In-situ Neutron Scattering on the NG1 Reflectometer UHV Techniques  Protective Environment  Epitaxial Thin Film Growth  Gas Loading (e.g. H)  Sputter Etching of Surface Material  RHEED Analysis  Mass Spectrometry Scattering Techniques  Specular Reflectometry  Off-Specular Scattering  Grazing Angle Diffraction  High Angle Diffraction  SANS Phenomena  Adsorption / Desorption  Diffusion  Segregation  Morphology  Crystallography  Magnetism  Superconductivity Joe Dura NIST-NCR

49. SNS Experimental FacilitiesOak Ridge X0000910/arb 49 Reflectometry In addition to providing a unique probe for magnetic surfaces and multi-layers polarized neutrons permit direct inversion to obtain the scattering length density profile - no phase problem – a magnetic reference layer buried in the substrate can have magnetization wrt neutron polarization varied – for a weak absorbtion probe (valid for the neutron) three known references lead to unique solution – drawback is the price paid in sensitivity for polarized beam Off-specular reflection for in-plane structure

50. SNS Experimental FacilitiesOak Ridge X0000910/arb 50 SNS Reflectometers 2 reflectometers sharing a single beamport Requires new multi- channel shutters in the target station Allows for both vertical sample (magnetism) and horizontal sample (liquids) studies Novel beam bender optics allows multiplexing and reduces background Reflectivities <10 -9, 10-50 times faster than any existing instrument 2000-03451/arb

51. SNS Experimental FacilitiesOak Ridge X0000910/arb 51 Instrument features Views coupled 20-K H 2 moderator from beamline 4TD Shares beamline with magnetism reflectometer Multi-channel beam bender eliminates all < 1.5 Å Three bandwidth choppers allow clean operation in 0.5-4.5, 5-9, or 9.5-13.5 Å wavelength frames Tapered guide delivers angular bandwidth that can be sampled by slits at 0 <  < 7° relative to the horizontal 1-mm 2 -resolution PSD permits study of off-specular and grazing-incident small-angle scattering For liquid samples 0 < Q < 0.5 Å -1 is accessible; by tilting a solid surface, 0 < Q < 1.0 Å -1 (R min ~ 4×10 -10 )

52. SNS Experimental FacilitiesOak Ridge X0000910/arb 52 Schematic Source Microguide Bender Tapered Guide Slits Detector 14.5 m Bandwidth Choppers Bender/tapered guide combination eliminates source line-of-sight Tapered guide delivers angular bandwidth that allows multiple angles of incidence

53. SNS Experimental FacilitiesOak Ridge X0000910/arb 53 Microguide bender 4  c Ni Bender acts as high-pass wavelength filter Multiple channels n transmit higher flux [Left]: Phase-space acceptance at 5-channel bender exit for 9-Å neutrons after 0-5 bounces (red-green). [Right]: Integrated acceptance for n-channel benders.

54. SNS Experimental FacilitiesOak Ridge X0000910/arb 54 Reflectometer beam benders Bender inside wide shutter deflects the beam downward to a 4.75° angle onto sample surface. Sample

55. SNS Experimental FacilitiesOak Ridge X0000910/arb 55 Tapered guide Tapered guide provides angular bandwidth for liquid measurement. Slits select sample incident angle about  = 4.75° centerline. 12 cm 1.75 cm 4  c Ni Contours represent ratio of actual to maximum optical acceptance (X / X max ) at tapered guide exit.

56. SNS Experimental FacilitiesOak Ridge X0000910/arb 56 Slits  = 2.06°;  = 0.0014; X / X max = 0.89; m avg = 3.3  = 4.75°;  = 0.0061; X / X max = 0.86; m avg = 1.3 Slit settings off the  = 4.75° centerline exhibit higher average number of bounces m avg. Judicious selection of incident angle  ensures optimal acceptance X.

57. SNS Experimental FacilitiesOak Ridge X0000910/arb 57 Liquids reflectometer

58. SNS Experimental FacilitiesOak Ridge X0000910/arb 58 Performance comparison POSY-II MURR ADAM, NG-1 SURF SNS reflectometers will accumulate specular reflectivity data 10-50 times faster than the best existing instruments. Improved Q max will yield near-atomic-scale layer-thickness sensitivity. Simulated data from 10-Å SiO 2 layer atop Si. SNS-L utilizes 12 incident angles  i to measure Q max > 0.9 Å -1 in  t < 5 hours (18,000 s). Arrows indicate reflectivities measured in 12-24 hours (40-80,000 s) by existing instruments.  i  t i (s)

59. SNS Experimental FacilitiesOak Ridge X0000910/arb 59 SNS Powder Diffractometer

60. SNS Experimental FacilitiesOak Ridge X0000910/arb 60 Detector Array

61. SNS Experimental FacilitiesOak Ridge X0000910/arb 61 Characteristics of Major Components Source/Moderator - decoupled poisoned ambient water  t 0 = 10  s at = 1 Å Incident Flight Path - 60 m moderator-sample distance curved supermirror guide with 3  c Ni coating, 1.5 cm wide x 3 cm tall ~ 8 m moderator-guide distance adjustable  9 m guide-sample distance Chopper System - T o and 2 bandwidth/frame-overlap choppers Collimators - variable aperture for incident beam inside scattering chamber - oscillating radial collimator outside scattering chamber - fixed radial collimators Detectors - type TBD 10 ° – 170 ° in-plane, ± 30 ° out-of-plane coverage ( ± 45 ° at 90 ° ) 40 mm tall x 5 mm wide pixel size ~ 6 ster solid angle coverage, ~ 47 m 2 area 1 – 6 m variable distance from sample

62. SNS Experimental FacilitiesOak Ridge X0000910/arb 62 Narrow Bandwidth Concept Previous TOF diffractometers used detector "banks" at a few angles, along with a broad wavelength range to produce a limited number of data sets of intensity vs. wavelength. A new idea put forward by Paolo Radaelli proposes the use of wide angular coverage and full 60 Hz operation to collect a single data set of intensity vs. angle and time-of-flight. These spectra would then be combined "appropriately" after-the-fact to produce a single histogram with intensity vs. d-spacing. This new data collection/analysis concept can be applied to any detector geometry. However, it appears optimally suited to a continuous detector locus, with this locus chosen to optimize the resolution as a function of d-spacing.

63. SNS Experimental FacilitiesOak Ridge X0000910/arb 63 D-spacing-Lambda Space Coverage

64. SNS Experimental FacilitiesOak Ridge X0000910/arb 64 GEM Powder Diffractometer at ISIS

65. SNS Experimental FacilitiesOak Ridge X0000910/arb 65 Detector Locus

66. SNS Experimental FacilitiesOak Ridge X0000910/arb 66 D-spacing Coverage of POW-GEN3

67. SNS Experimental FacilitiesOak Ridge X0000910/arb 67 D-spacing Coverage of POW-GEN3

68. SNS Experimental FacilitiesOak Ridge X0000910/arb 68 Instrument Resolution Function

69. SNS Experimental FacilitiesOak Ridge X0000910/arb 69 Neutron Source

70. SNS Experimental FacilitiesOak Ridge X0000910/arb 70 Neutron Source

71. SNS Experimental FacilitiesOak Ridge X0000910/arb 71 Simulated Diffraction Experiment

72. SNS Experimental FacilitiesOak Ridge X0000910/arb 72 Simulated Diffraction Experiment

73. SNS Experimental FacilitiesOak Ridge X0000910/arb 73 Another Variation on Powder Diffraction: Residual Strain

74. SNS Experimental FacilitiesOak Ridge X0000910/arb 74 SNS SANS

75. SNS Experimental FacilitiesOak Ridge X0000910/arb 75 Schematic Layout

76. SNS Experimental FacilitiesOak Ridge X0000910/arb 76 Bender System: guide-bender-guide

77. SNS Experimental FacilitiesOak Ridge X0000910/arb 77 Bender System: Performance

78. SNS Experimental FacilitiesOak Ridge X0000910/arb 78 Choppers

79. SNS Experimental FacilitiesOak Ridge X0000910/arb 79 Soller Collimators: Configuration

80. SNS Experimental FacilitiesOak Ridge X0000910/arb 80 Soller Collimators: Direct Beam

81. SNS Experimental FacilitiesOak Ridge X0000910/arb 81 Soller Collimators: Resolution and Flux

82. SNS Experimental FacilitiesOak Ridge X0000910/arb 82 Low Angle Detector Needed: 1 x 1 m 2  5mm resolution  1Å 10 3 n/s/pixel 4 x 10 7 n/s/detector low background Needed: 1 x 1 m 2  5mm resolution  1Å 10 3 n/s/pixel 4 x 10 7 n/s/detector low background Available ( 3 He): 1 x 1 m 2 7 mm resolution  5Å 10 4 n/s/wire 10 6 n/s/detector Low background Available ( 3 He): 1 x 1 m 2 7 mm resolution  5Å 10 4 n/s/wire 10 6 n/s/detector Low background 1.25  2.5 bar (concave structure) counting efficiency resolution counting rate 5mm wire spacing. 1.25  2.5 bar (concave structure) counting efficiency resolution counting rate 5mm wire spacing.

83. SNS Experimental FacilitiesOak Ridge X0000910/arb 83 High Angle Detectors 20 x Standard 3 He PSD

84. SNS Experimental FacilitiesOak Ridge X0000910/arb 84 Performance: Flux at the End of the Bender-Sytem

85. SNS Experimental FacilitiesOak Ridge X0000910/arb 85 Performance: Flux at Sample (14m)

86. SNS Experimental FacilitiesOak Ridge X0000910/arb 86 Performance: Flux vs. Collimation Max. counting rate: 700n/s/pixel at 1m collimation 100n/s/pixel at 4m collimation

87. SNS Experimental FacilitiesOak Ridge X0000910/arb 87 Q-Coverage protein lipid(solvent) Qmin= 0.004 Å -1 (Pinhole) = 0.001 Å -1 (Soller) Qmax = 12Å -1 (1 st Frame) = 3.3Å -1 (2 nd Frame) = 1.6Å -1 (3 rd Frame) 3 rd Frame 1 st Frame Huey Huang Rice University

88. SNS Experimental FacilitiesOak Ridge X0000910/arb 88 Performance (low angle detector)

89. SNS Experimental FacilitiesOak Ridge X0000910/arb 89 Performance

90. SNS Experimental FacilitiesOak Ridge X0000910/arb 90 100Å Guide Detector 4m Performance : MC simulation