Cinematic reflectometry using QIKR, the quite intense kinetics reflectometer

Abstract

The Quite Intense Kinetics Reflectometer (QIKR) will be a general-purpose, horizontal-sample-surface neutron reflectometer. Reflectometers measure the proportion of an incident probe beam reflected from a surface as a function of wavevector (momentum) transfer to infer the distribution and composition of matter near an interface. The unique scattering properties of neutrons make this technique especially useful in the study of soft matter, biomaterials, and materials used in energy storage. Exploiting the increased brilliance of the Spallation Neutron Source Second Target Station, QIKR will collect specular and off-specular reflectivity data faster than the best existing such machines. It will often be possible to collect complete specular reflectivity curves using a single instrument setting, enabling “cinematic” operation, wherein the user turns on the instrument and “films” the sample. Samples in time-dependent environments (e.g., temperature, electrochemical, or undergoing chemical alteration) will be observed in real time, in favorable cases with frame rates as fast as 1 Hz. Cinematic data acquisition promises to make time-dependent measurements routine, with time resolution specified during post-experiment data analysis. This capability will be deployed to observe such processes as in situ polymer diffusion, battery electrode charge–discharge cycles, hysteresis loops, and membrane protein insertion into lipid layers.

Studying Transient Phenomena in Thin Films with Reinforcement Learning

“…A discussion of this pulse-skipping approach is described elsewhere. 15 The scattering angle was chosen to be θ = 0.6°, which corresponds to a range of 0.0015 < q < 0.057 Å −1 for the selected wavelengths. This compromise allows for the highest rate of reflected neutrons in a wide enough q range, where changes are expected to be large enough to be modeled.…”

“…For the time-resolved measurements presented here, we chose a wavelength band center of λ c = 5.9 Å, allowing us to make use of the LR beam flux peak at about 2 Å. A discussion of this pulse-skipping approach is described elsewhere …”

Second Target Station Project: STS/PSD/ESTD Workshop on Batteries and Energy Storage

“…• BWAVES -broadband spectrometer [14] • CENTAUR -small-angle and wide-angle scattering instrument [15] • CHESS -cold neutron spectrometer [16] • CUPI2D -neutron imaging [17] • EXPANSE -wide-angle neutron spin echo [18] • PIONEER -single-crystal diffractometer [19] • QIKR -kinetics reflectometer [20] • VERDI -polarized diffractometer [21]…”

Second Target Station Project: STS Cross-Directorate Workshop on Hydrogen Fuel

“…The first session of the workshop started with an overview of the Second Target Station project, followed by presentations on new capabilities of the initial 8 instruments, covering a broad spectrum of scattering techniques, from reflectometry (QIKR [13]), imagining (CUPI 2 D [14]), small/wide angle scattering (CENTAUR [15]), diffraction (PIONEER [16] and VERDI [17]), and spectroscopy (BWAVE [18], CHESS [19], EXPANSE [20]).…”