Simulating and benchmarking neutron total scattering instrumentation from inception of events to reduced and fitted data

2021 ◽  
Vol 54 (4) ◽  
Author(s):  
Peter C. Metz ◽  
Thomas Huegle ◽  
Daniel Olds ◽  
Katharine Page
Keyword(s):  
Neutron Scattering ◽  
Simulated Data ◽  
Real Space ◽  
Spallation Neutron Source ◽  
Total Scattering ◽  
Range Resolution ◽  
Design Characteristics ◽  
Event Based ◽  
Heuristic Analysis ◽  
Neutron Total Scattering

In the design and realization of modern neutron scattering instrumentation, particularly when designing beamline concepts from the ground up, it is desirable to fully benchmark against realistically simulated data. This is especially true for total scattering beamlines, where the future deliverable data is to be analysed in both reciprocal- and real-space representations, and needs must be carefully balanced to ensure sufficient range, resolution and flux of the instrument. An approach to optimize the design of neutron scattering instrumentation via a workflow including ray-tracing simulations, event-based data reduction, heuristic analysis and fitting against realistically simulated spectra is demonstrated here. The case of the DISCOVER beamline concept at the Spallation Neutron Source is used as an example. The results of the calculations are benchmarked through simulation of existing instrumentation and subsequent direct comparison with measured data. On the basis of the validated models, the ability to explore design characteristics for future beamline concepts or future instrument improvements is demonstrated through the examples of detector tube size and detector layout.

MCGRtof: Monte CarloG(r) with resolution corrections for time-of-flight neutron diffractometers

2001 ◽  
Vol 34 (6) ◽  
pp. 780-782 ◽  
Author(s):  
Matthew G. Tucker ◽  
Martin T. Dove ◽  
David A. Keen
Keyword(s):  
Pair Distribution Function ◽  
Time Of Flight ◽  
Distribution Functions ◽  
Monte Carlo Algorithm ◽  
Scattering Data ◽  
Spallation Neutron Source ◽  
Total Scattering ◽  
Inverse Monte Carlo ◽  
Pair Distribution Functions ◽  
Neutron Total Scattering

A new implementation of the programMCGR[Pusztai & McGreevy (1997).Physica B,234–236, 357–358] for the calculation of pair distribution functions from neutron total scattering data using an inverse Monte Carlo algorithm is presented. The new implementation, calledMCGRtof, incorporates the resolution functions for time-of-flight neutron diffractometers, and is suitable for analysis of data from instruments such as GEM at the ISIS spallation neutron source. The effect of including resolution correctly is to increase the magnitude of the pair distribution function at larger distances. The working program is illustrated with total scattering measurements from crystalline AlPO4.

Neutron Total Scattering and Inelastic Neutron Scattering

2004 ◽  
Vol 46 (6) ◽  
pp. 390-398
Author(s):  
Takashi KAMIYAMA ◽  
Shinichi ITOH ◽  
Toshiharu FUKUNAGA ◽  
Kazuma HIROTA
Keyword(s):  
Neutron Scattering ◽  
Inelastic Neutron Scattering ◽  
Inelastic Neutron ◽  
Total Scattering ◽  
Neutron Total Scattering

scholarly journals Event-based processing of neutron scattering data at the Spallation Neutron Source

2018 ◽  
Vol 51 (3) ◽  
pp. 616-629 ◽  
Author(s):  
Garrett E. Granroth ◽  
Ke An ◽  
Hillary L. Smith ◽  
Pamela Whitfield ◽  
Joerg C. Neuefeind ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Neutron Source ◽  
National Laboratory ◽  
Scattering Data ◽  
Spallation Neutron Source ◽  
Pump Probe ◽  
New Era ◽  
Oak Ridge ◽  
Battery Degradation ◽  
Event Based

The Spallation Neutron Source at Oak Ridge National Laboratory, USA, ushered in a new era of neutron scattering experiments through the use of event-based data. Tagging each neutron event allows pump–probe experiments, measurements with a parameter asynchronous to the source, measurements with continuously varying parameters and novel ways of testing instrument components. This contribution will focus on a few examples. A pulsed magnet has been used to study diffraction under extreme fields. Continuous ramping of temperature is becoming standard on the POWGEN diffractometer. Battery degradation and phase transformations under heat and stress are often studied on the VULCAN diffractometer. Supercooled Al2O3 was studied on NOMAD. A study of a metallic glass through its glass transition was performed on the ARCS spectrometer, and the effect of source variation on chopper stability was studied for the SEQUOIA spectrometer. Besides a summary of these examples, an overview is provided of the hardware and software advances to enable these and many other event-based measurements.

A Bayesian approach to removal of incoherent scattering from neutron total-scattering data

2014 ◽  
Vol 47 (6) ◽  
pp. 2060-2068 ◽  
Author(s):  
Anton Gagin ◽  
Igor Levin
Keyword(s):  
Probability Distributions ◽  
Simulated Data ◽  
Incoherent Scattering ◽  
Scattering Data ◽  
Data Sets ◽  
Background Signal ◽  
Total Scattering ◽  
Public Domain Software ◽  
Principle Of Maximum ◽  
Neutron Total Scattering

A Bayesian statistics approach for subtraction of incoherent scattering from neutron total-scattering data has been developed and implemented in a public domain software package. In this approach, the estimated background signal associated with incoherent scattering maximizes the posterior probability, which combines the likelihood of this signal in reciprocal and real spaces with the prior that favors smooth lines. The probability distributions are constructed according to the principle of maximum entropy. The method enables robust subtraction of incoherent-scattering backgrounds while providing estimated uncertainties for recovered signals. The developed procedure was first tested using simulated data and then demonstrated using three representative experimental data sets, collected on bulk materials and nanoparticles, featuring distinct ratios of coherent to incoherent scattering.

Relationship between low-Q peak and long-range ordering of ionic liquids revealed by high-energy X-ray total scattering

2015 ◽  
Vol 17 (27) ◽  
pp. 17838-17843 ◽  
Author(s):  
Kenta Fujii ◽  
Shinji Kohara ◽  
Yasuhiro Umebayashi
Keyword(s):  
Ionic Liquids ◽  
Long Range ◽  
High Energy ◽  
Real Space ◽  
Space Structure ◽  
Total Scattering ◽  
X Ray ◽  
Peak Intensity ◽  
Long Range Ordering

A new function, SQpeak(r); a connection between low-Q peak intensity with real space structure.

Total scattering experiments on glass and crystalline materials at the ESRF on the ID11 Beamline

2014 ◽  
Vol 30 (S1) ◽  
pp. S2-S8 ◽  
Author(s):  
Andrea Bernasconi ◽  
Jonathan Wright ◽  
Nicholas Harker
Keyword(s):  
High Energy ◽  
Real Space ◽  
European Synchrotron Radiation Facility ◽  
Small Sample ◽  
Distribution Functions ◽  
Total Scattering ◽  
Crystalline Materials ◽  
Space Resolution ◽  
Atomic Pair ◽  
Counting Statistics

ID11 is a multi-purpose high-energy beamline at the European Synchrotron Radiation Facility (ESRF). Owing to the high-energy X-ray source (up to 140 keV) and flexible, high-precision sample mounting which allows small sample–detector distances to be achieved, experiments such as total scattering in transmission geometry are possible. This permits the exploration of a wide Q range and so provides high real-space resolution. A range of samples (glasses and crystalline powders) have been measured at 78 keV, first putting the detector as close as possible to the sample (~10 cm), and then moving it vertically and laterally with respect to the beam in order to have circular and quarter circle sections of diffraction rings, with consequent QMAX at the edge of the detector of about 16 and 28 Å−1, respectively. Data were integrated using FIT2D, and then normalized and corrected with PDFgetX3. Results have been compared to see the effects of Q-range and counting statistics on the atomic pair distribution functions of the different samples. A Q of at least 20 Å−1 was essential to have sufficient real-space resolution for both type of samples while statistics appeared more important for glass samples rather than for crystalline samples.

Autocorrelation function of the spin misalignment in magnetic small-angle neutron scattering: application to nanocrystalline metals

2013 ◽  
Vol 46 (3) ◽  
pp. 788-790 ◽  
Author(s):  
Andreas Michels ◽  
Jens-Peter Bick
Keyword(s):  
Neutron Scattering ◽  
Autocorrelation Function ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Anisotropy Field ◽  
Real Space ◽  
Scattering Data ◽  
Stiffness Constant ◽  
The Mean ◽  
Cobalt And Nickel

Real-space magnetic small-angle neutron scattering data from nanocrystalline cobalt and nickel have been analysed in terms of a recently developed micromagnetic theory for the autocorrelation function of the spin misalignment [Michels (2010).Phys. Rev. B,82, 024433]. The approach provides information on the exchange-stiffness constant and on the mean magnetic `anisotropy-field' radius.

scholarly journals Advances in utilizing event based data structures for neutron scattering experiments

2018 ◽  
Vol 89 (9) ◽  
pp. 093001
Author(s):  
Peter F. Peterson ◽  
Daniel Olds ◽  
Andrei T. Savici ◽  
Wenduo Zhou
Keyword(s):  
Neutron Scattering ◽  
Data Structures ◽  
Event Based
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