Momentum and energy dependent resolution function of the ARCS neutron chopper spectrometer at high momentum transfer: Comparing simulation and experiment

Diallo, Souleymane; Lin, Jiao; Abernathy, D. L.; Azuah, R. T.

doi:10.1016/j.nima.2016.08.027

Cited by 6 publications

(4 citation statements)

References 37 publications

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“…To extract the intrinsic dynamical features from these Q ‐resolved QENS data, it is necessary to account for the instrumental resolution effects and other background contributions . As already explained above, the standard procedure for dealing with QENS data is to determine the best analytical scattering model S d ( Q , E ) which, when convoluted with the instrument resolution function, reproduces the experimental data.…”

Section: Resultsmentioning

confidence: 99%

Side chain dynamics in semiconducting polymer MEH‐PPV

Osti

Mamontov

Daemen

et al. 2018

J of Applied Polymer Sci

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The characteristic nanoscale dynamics of the alkyl side groups in the light‐emitting polymer poly[2‐methoxy‐5‐(2′‐ethyl‐hexyloxy)‐1,4‐phenylene vinylene] have been investigated using quasi‐elastic neutron scattering (QENS). The measurements were taken below the polymer's glass transition (T ≤ Tg ≃ 353 K), where the main backbone is in a rigid state and does not contribute to the broadening of the QENS signal. An analytical diffusion model consisting of a static term and two dynamical components, characterizing the flexible side groups, provide an excellent fit to the experimental data. The two observed dynamical processes are all localized in character, with no meaningful dependence on temperature. The faster process, with characteristic timescale of ∼18 ps at room temperature (RT), can be linked to the average mobility of the terminal protons of the alkyl chain, while the slower process, with characteristic timescale of ∼170 ps at RT, to those protons at the other end of the alkyl chain, closest to the backbone. While the fraction of mobile protons contributing to the QENS signal increases with increasing temperature, the characteristic timescale and confining volume within which the protons are able to move locally depend chiefly on the polymer conformational state. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47394.

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Section: Resultsmentioning

confidence: 99%

Side chain dynamics in semiconducting polymer MEH‐PPV

Osti

Mamontov

Daemen

et al. 2018

J of Applied Polymer Sci

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“…MCViNE has been improved in the last four years in software infrastructure and interfaces for users. Applications of the MCViNE package at SNS include assisting design of new instruments at the second target station, design of sample environments and collimators, as well as advanced data analysis [9,11,26,27]. MCViNE is an ongoing project.…”

Section: Discussionmentioning

confidence: 99%

“…MCViNE simulations were also performed to study the effects of instrument broadening on measured data. For example, detailed MCViNE simulations of powder 4 He data measured at ARCS [9,10] and single crystal spin-wave data for V 2 O 3 measured at SEQUOIA [11] were used to examine and confirm the material and resolution models.…”

Section: Introductionmentioning

confidence: 99%

Recent developments of MCViNE and its applications at SNS

et al. 2019

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MCViNE is an open source, object-oriented Monte Carlo neutron ray-tracing simulation software package. Its design allows for flexible, hierarchical representations of sophisticated instrument components such as detector systems, and samples with a variety of shapes and scattering kernels. Recently this flexible design has enabled several applications of MCViNE simulations at the Spallation Neutron Source (SNS) at Oak Ridge National Lab, including assisting design of neutron instruments at the second target station and design of novel sample environments, as well as studying effects of instrument resolution and multiple scattering. Here we provide an overview of the recent developments and new features of MCViNE since its initial introduction (Jiao et al 2016 Nucl. Instrum. Methods Phys. Res., Sect. A 810, 86-99), and some example applications.

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“…Monte Carlo neutron ray tracing simulations with the MCViNE package 41 can capture these details, and are used to calculate the PSF functions by taking relevant factors into account: modeling the neutron beam, the sample with a δ-function scattering kernel with a geometric shape and scattering cross section same as the real sample, and the detector system in high accuracy 20,[41][42][43] . In Figure 1C examples of MCViNE-simulated, energy-dependent energy resolution functions are presented.…”

Section: B Point Spread Functionmentioning

confidence: 99%

Super-resolution energy spectra from neutron direct-geometry spectrometers

Islam

Lin

Archibald

et al. 2019

Review of Scientific Instruments

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Neutron direct-geometry time-of-flight chopper spectroscopy is instrumental in studying fundamental excitations of vibrational and/or magnetic origin. We report here that techniques in super-resolution optical imagery (which is in real -space) can be adapted to enhance resolution and reduce noise for a neutron spectroscopy (an instrument for mapping excitations in reciprocal space). The procedure to reconstruct super-resolution energy spectra of phonon density of states relies on a realization of multi-frame registration, accurate determination of the energy-dependent point spread function, asymmetric nature of instrument resolution broadening, and iterative reconstructions. Applying these methods to phonon density of states data for a graphite sample demonstrates contrast enhancement, noise reduction, and ∼5-fold improvement over nominal energy resolution. The data were collected at three different incident energies measured at the Wide Angular-Range Chopper Spectrometer at the Spallation Neutron Source. a) Both authors contributed equally to this manuscript b) Electronic mail: linjiao@ornl.gov; Both authors contributed equally to this manuscript c) Electronic mail: granrothge@ornl.gov 1 arXiv:1906.09482v1 [physics.data-an]

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Momentum and energy dependent resolution function of the ARCS neutron chopper spectrometer at high momentum transfer: Comparing simulation and experiment

Cited by 6 publications

References 37 publications

Side chain dynamics in semiconducting polymer MEH‐PPV

Side chain dynamics in semiconducting polymer MEH‐PPV

Recent developments of MCViNE and its applications at SNS

Super-resolution energy spectra from neutron direct-geometry spectrometers

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