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Future Trends in Neutron Scattering at the Component LevelPresented at

DENIM 2019North Bethesda, MD

Richard IbbersonNeutron Sciences Directorate

September 17-19, 2019

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Lessons learned from a personal perspective…

Spallation Neutron Source (1.4 MW) High Flux Isotope Reactor (85 MW)

Neutron Beam Split-Core Reactor (20 MW) ISIS Facility (0.2 MW)

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Look back before looking forward…

ca. 1979 2019

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Lessons learned #1

Never use sports analogies when attempting to communicate to (most) scientists

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Look back before looking forward… A personal journey from “Holdsworth professional” to “Specialized Venge”…

ca. 1979 2019

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Outline• Overview

– Lessons learned – a personal perspective– High-level trends and cross-cutting themes

• Neutron Optics – innovations and new capabilities – Evolution of supermirrors – Nested K-B Mirrors– Wolter optics

• Detectors– Evolution of scintillator detectors– Energy-selective analyzers– High spatial resolution Anger cameras

• Adopting new materials and technologies

• Summary

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Accelerator and reactor-based neutron sources are complementary

Highest peak neutron intensities Highest steady-state neutron fluxes (more neutrons)

Superior for many aspects of neutron scattering

Superior for isotope production and materials irradiation as well as selected aspects of neutron scattering

Superior for studying phenomena across broad spatial and temporal regions

Superior at focusing on phenomena at specific length and time scales

Pulsed accelerator sources Steady-state reactors

CSNS, ESS, SNS-FTS(-STS), J-PARC, PSI-SINQ, STFC-ISIS Facility ANSTO, FRM II, HFIR, ILL, NCNR, …

88

High-level Trends looking ahead

• High-brightness beams at Spallation Sources

• Energy-selective multiplexing at Reactor Sources

…and cross-cutting themes– Advanced materials and manufacturing methods– Improved understanding of current materials(!)– High-performance computing (HPC) and electronics– Modelling and simulations

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Neutron Optics – innovations and new capabilities

“The problem with neutrons is that there’s just not that many of them. ‘The number of neutrons produced here, <name your preferred intense source>, is about the same as the number of photons produced by a candle….”

1010M.W. Johnson, McGuide, RAL-80-065.

90 m long, 36 km radius of curvature

“cropped” elliptical cross-section in x- and y-dimensions

graded m=3 → m=1.5 supermirror coating

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COMPONENT Source = ISIS_moderator(Face = "hrpd", E0 = emin, E1 = emax, dist = 3.649, xw = 0.025,yh = 0.08, modXsize = 0.1, modYsize = 0.1, CAngle = 0,SAC=1)AT (0,0,0) ABSOLUTE

COMPONENT Channeled_guide1 = Channeled_guide(w1 = 0.02500, h1 = 0.08000, w2 = 0.02500, h2 = 0.08000, l = 0.5,mx = 3, my = 3)AT (0,0,3.65) RELATIVE Source

COMPONENT Channeled_guide2 = Channeled_guide(w1 = 0.02500, h1 = 0.08000, w2 = 0.02500, h2 = 0.08000, l = 0.5,mx = 3, my = 3)AT (0,0,4.15) RELATIVE Source

COMPONENT Channeled_guide3 = Channeled_guide(..................................

COMPONENT Channeled_guide179 = Channeled_guide(w1 = 0.0232, h1 = 0.0436, w2 = 0.0217, h2 = 0.0419, l = 0.5,mx = 3, my = 3)AT (-0.08810,0.00000,92.49994) RELATIVE SourceROTATED(0,0,0) relative Channeled_guide112

COMPONENT Channeled_guide180 = Channeled_guide(w1 = 0.0217, h1 = 0.0419, w2 = 0.0200, h2 = 0.0400, l = 0.35,mx = 3, my = 3)AT (-0.08883,0.00000,92.99994) RELATIVE SourceROTATED(0,0,0) relative Channeled_guide112

COMPONENT sample = PowderN(reflections = hkl_file, format = Fullprof, radius = COMPONENT

HRPD_backbank = TOFlog_spher(filename = "Detector_back.dat", radius = 1.0, theta_min = 160.0,theta_max = 176.0, time_min = tmin, time_max = tmax, dtovert =

dtt,theta_focus = 168.329,phi_min=-67.5,phi_max=67.5,nelements=60)

AT (0, 0, 0) RELATIVE sample

ca. 2007

ca. 1980

Advances in Monte Carlo modelling –designing a 100m-long guide for HRPD, ISIS Facility

1111

Design of 170m-long guides for the ESS

Single pinhole

Double-pinholebeamstop

Double-pinholekinked

Double-pinholecurved

Sonja Holm-Dahlin et al. Quantum Beam Sci. 2019, https://doi.org/10.3390/qubs3030016

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Advances in sputtering and super-polishing now support large scale fabrication of high-m coatings….

Reflectivity profiles of Ni/Ti supermirror coatings

https://www.swissneutronics.ch/products/neutron-supermirrors/

Ni/Ti supermirrors on metallic substrates

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… and this supports use of increasingly complex multi-channel (in-pile) monoliths

https://www.swissneutronics.ch/

NB-5GP-SANS-1.7899,-5.0000

(40.0 x 40.0)H: -0.0220V:0.0000

NB-6MANTA

55.9122, 25.3870(50.0, 114.0)H: 0.68807V: 0.31243

NB-4Imaging

-53.7137, -8.3711(40.0 x 50.0)H: 0.66101V: 0.00000

NB-3BioSANS

-53.7137, 40.6289 (40.0 x 40.0)H: 0.66101V:0.50000

NB-1IMAGINE-53.7137, 83.6289

(40.0 x 40.0)H: 0.66101V: 1.02887

-1.79, 66.13(54.0 x 83.5)

3mm

4mm 4mm

12.7

021

mm

11.9

238

mm

NB-2Spin Echo-1.7899,59.0000

(40.0 x 80.0)H:-0.02200V: 0.72514

Installed at NIST…. In planning at HFIR….

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Imaging nested-mirror assemblies – A new generation of neutron delivery systems?

Olivier Zimmer Journal of Neutron Research, vol. 20, no. 4, pp. 91-98, 2018 DOI:10.3233/JNR-190101

• Characteristics– High brilliance transfer from source to instrument – Maximizes useable flux at sample (removes useless flux)– Versatile, options for beam tailoring e.g. size & divergence,

wavelength spectrum, polarization

Nested elliptical multi-mirror system, with common focal points M and M′

1515

Wolter optics – from X-ray telescopes to neutron scattering

Dan Hussey et al. J. Imaging 2018, 4(3), 50; doi.org/10.3390/jimaging4030050

• Used as neutron image forming optics (resolution determined by optics not L/D)

• Large distance between sample and optics (and optics and detector) allowsuse of bulky SE and in-beam devices

• Use of nested (nickel) mirrors to increase solid angle (higher count rate)

• Optical magnification can be used to improve spatial resolution

Wolter type I optic comprising confocal hyperboloid and ellipsoid

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Wolter Optics, Helium-3 Neutron Imaging of Magnetic Samples (WHIMS!)

Dan Hussey et al. J. Imaging 2018, 4(3), 50; doi.org/10.3390/jimaging4030050

Realized spatial resolution ~100 μm

Improved fabrication methods, development of (larger) nested shells could offer ~20 μm…

MENUS – Materials Engineering by NeUtron Scattering• Anisotropy in low

symmetry materials• Superlattice structures

and stress partitioning• In operando and

extreme fields• Kinetic phase transitions• High spatial resolution

strain scanning

SANS

70° detector

high angledetector

90° detector

Simulated diffraction of Ni3Al with super lattice structure at

(100) 3.58 Å

EWALD: Extended Wide Angle Laue Diffractometer

• Macromolecular neutron crystallography

• Minimum crystal size needed on MaNDi is 0.1 mm3 (2016)

• ~60×flux of MaNDi at FTS

Neutron optics and polarization development

1919

Neutron Detectors – innovations and new technologies

“…And the problem with detecting neutrons is akin to spotting that candle in the middle of a big field on a dark and stormy night…..”

2020

Multiplexing - how to maximize detector solid angle remains a perennial engineering challenge…

POLARIS (ISIS Facility) detector tank (ca. 2011) and some of the 38 6LiF:ZnS(Ag) detector modules. (924 single cathode PMTs & some 460 km of clear fibre optic.)

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Adopting and prototyping new (scintillator) detector technology

Prototype ZnS:Ag/6LiF scintillation detector for IMAT, ISIS Facility. (200 pixels, 100x4 mm2, 64-channel flat panel PMT.)

• Flat panel multi-anode photo-multiplier tubes

• Wavelength-shifting fibre

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Multiplexing - how to maximize detector solid angle remains a perennial engineering challenge…

Anger Camera arrays installed at MANDI (40); TOPAZ (25); and envisioned for EWALD.

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Adopting and prototyping new detector technology –Anger Cameras

Prototype GS20 (Li-glass) Anger camera (SNS: MANDI, TOPAZ, SNAP; HFIR HB-3A)

• Silicon photomultiplier diodes (SiPMs)– Tiling without loss of resolution– Magnetic field immune – Improved angular resolution at less than

half the cost!

2 x 2 array of SensL –ArrayC-60035 modules115 x 115 mm2

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Detector multiplexing has measurable science productivity impact

Productivity measures at HB-3A (HFIR.)

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Multiplexing – an energy dispersive detector

Neutrons diffract from a highly-ordered pyrolytic graphite crystals to corresponding neutron counters

• Neutron Energy Analysis on CANDOR (NCNR)– 4-6 Å white beam analyzed simultaneously over ~5°– 20 arrays make up angular spread– 54 detectors /array – Potential for 1000x faster than single detector

Note presentations by: Kevin Pritchard, Joshua Graybill, Nancy Hadad

2626

Research and development of the CANDOR module

Full-scale prototype

– 6LiF:ZnS(Ag) scintillator– Embedded WLS fibres– SiPMs

2727

Advancing new materials and manufacturing methods for scintillators?

• 6LiF:ZnS(Ag) scintillator– count-rate limitations– materials processing issues

• GS-20 LiF-glass – 1960s technology (quantum limited)– LiI alternatives

• 6LiF:ZnO(Zn) scintillator– low afterglow enables higher rates

Back to basics:Neutron Capture – 6LiIonization - ZnS(Ag)Other: Light Collection - WLS

Signal Strength – SiPMSignal Processing

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Advanced materials and technologies

• Carbon fibre technology– Progress in the manufacturing technique of radially oriented carbon fibre reinforced polymer (oCFRP) disks– Choppers of 750 mm diameter rotating at 315 Hz corresponding to a circumferential speed of 746 m s−1

• Magnetic bearings– Next-generation optics less vibration tolerant– Minimize translations to <0.01 mm, rotations <0.001°– (Scott Olsen – Chopper Breakout session)

• Additive Manufacturing– (David Anderson – presentation, Breakout session)

CHESS (SNS-STS) high-speed translation-stage mounted chopper concept

(Bill McHargue – poster)

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Lessons learned #2

Not-invented-here syndrome –acknowledge it exists

3030

Not-invented-here syndrome: a case study…

1989 Tour de FranceGreg LeMond beats Laurent Fignon by 8 seconds in the closest ever finish

3131

Looking to the future • Modern focusing optics and high-resolution detectors are pushing current limits for

accuracy and precision of installation and operation – (Van Graves – poster)

• And they present new challenges that must be overcome e.g. vibration sensitivity, diurnal temperature sensitivity, floor compliance/changes in floor loading, site settling, etc.

• Solutions may already by at hand from other communities – Synchrotron light sources?

• Be on the look out for and and open to new technology and materials– There is still a need for fundamental materials research

3232

Lessons learned #3

There’s more to life than neutron scattering…

3333

Future trends…and where to implement them?

Spallation Neutron Source (1.4 MW)

ISIS-II MW-class short-pulseNCNR cold source & guide replacement

SNS-Second Target Station & Proton Power Upgrade

HFIR Be-reflector change &Instrument & guide upgrades

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Questions…

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