Abstract: I will show the power of the off-specular scattering (OSS) technique combined with specular reflec-tion (SR) to probe the properties of interfaces, mainly focused on Soft Matter. Although applicable to both X-ray (XRR) and Neutron Reflectometry (NR, in monochromatic and Time-of-Flight (ToF) modes) the focus will be on ToF-NR, which is used more often for Soft Matter reflectometry nowa-days. I will present a novel combined SR and OSS data analysis framework, obtained using a quick and robust originally developed algorithm, including a common absolute scale normalization of both types of scattering, which are intricately linked, constraining the model to a high degree. After an introduction, I will show several example studies using this approach in the field of thin polymer films. I will also present a way for qualitative interpretation of OSS data without quantitative fitting, by a simple eye inspection of OSS maps plotted in different spaces.
[1] A. Hafner et al., J. Appl. Cryst. (2021), 54, 924.
[2] A. Hafner et al., J. Phys.: Condens. Matter (2021), 33, 364002.

Abstract: Liquid surfaces are important not only for its subtle properties, but also for serving as substrates and reaction platforms in many applications, ranging from biomembranes, lipid-based pharmaceutics to synthesis of 2D COF/MOFs. The Langmuir GID setup at the beamline P08 at PETRA III is dedicated to liquid surfaces and Langmuir layers, providing grazing incidence X-ray scattering (GIXS) data up to 2.5/Å in both Qxy and Qz within half minute. The remaining challenge had been complementarily acquiring the layer structures, that was conventionally measured by reflectometry (XR). The latter requires a complex optics to deflect the synchrotron beam to vary incidence onto liquid surfaces, creating high background and compromises the GIXS data quality. A so-called pseudoreflectivity method has been developed jointly on the Langmuir GID setup and at 12ID at NSLS-II to overcome this challenge [1,2]. It allows one to acquire a reflectivity down to 10E-14 from liquid surfaces with a single GIXS exposure, hence eliminates the demand of varying incidence for layer structure acquisition. It is based on the extended capillary wave model (eCWM). The theory provides a single analytical expression to describe both the specular reflection and the diffuse scattering around it. The single expression both implies that reflectivity can be analytically derived from diffuse scattering signal measured via GIXS. Moreover, the eCWM analysis provides the bending modulus of a film on the liquid surfaces and subsequently intrinsic film structure, that is not directly accessible by reflectometry. Hence the GIXS-pseudoreflectivity method is faster, requires simpler instrument, and provides more information compared to the reflectometry. We have experimentally proven that pseudoreflectivity agrees with the reflectivity measured by reflectometry and can be applied to varies types of liquid surfaces, including surfactant layers on water, surface freezing layer of alkanes or viscous liquid surfaces.
[1] 10.1107/s1600576724002887
[2] 10.1103/znt1-fmx6

Abstract: Rare earth elements are utilized in a diverse range of modern and evolving technologies. Current methods for separating and purifying these elements involve their interactions at liquid interfaces. For example, the primary separations technique in current use, known as solvent extraction, involves molecular binding and assisted transport across liquid-liquid interfaces. Other techniques in development utilize rare earth element adsorption to liquid-vapor and liquid-solid interfaces. The development of these techniques has taken place largely in the absence of an understanding of interfacial distributions of rare earth elements, and of the binding, coordination, and ordering of rare-earth elements with molecular species at the interface. This provides an opportunity for the use of X-ray reflectivity and spectroscopy to investigate these issues. I will review some recent X-ray studies in this area, with an emphasis on the use of multiple techniques to understand rare earth element coordination at the liquid-vapor interface.

Abstract: Data derived from photon and neutron experiments are key to many scientific breakthroughs across disciplines ranging from medicine to engineering. Developments in data sources, instrumentation, and detectors lead to rapidly growing data volumes of increased complexity. These developments present both great opportunities and significant challenges to the community. Addressing them requires systematic and sustainable research data management where data acquisition, analysis, and availability are critically important. The DAPHNE4NFDI consortium (DAta from PHoton and Neutron Experiments for the National Research Data Infrastructure) responds to this need as part of the German National Research Data Infrastructure (NFDI) for harmonized, FAIR compliant data practices and a FAIR ecosystem for the photon and neutron communities. DAPHNE4NFDI develops and maintains community-acknowledged reference databases, integrates open-access repositories and databases, and provides technical tools for metadata collection and storage supporting national and international platforms, while offering and maintaining FAIR software. These efforts aim to establish international research data standards, train early-career researchers, and promote sustainable FAIR data practices and tools. In particular, our reflectivity use-case illustrates a model workflow for FAIR data profiting from machine learning algorithms for live analysis and closed loop experiments DAPHNE4NFDI profits from close collaboration between large scale facilities, academic institutions, IT specialists, and user communities, integrating FAIR principles throughout the entire data lifecycle - from data acquisition to long term preservation, publication, and reuse.

Abstract: The sample environment working group of ORSO have hosted several workshops over the last year to discuss specific sample environments for neutron and x-ray reflectometry. This included sessions on electrochemistry, furnaces and troughs. These sessions involved in-depth talks on sample environments and short flash talks from different scientists (in and out of facilities). The aim of these workshops was to provide a relaxed platform within which sample environments can be discussed and common issues identified. In this talk I will present some brief highlights from these workshops and present how we hope to build up this working group in future, including building up a list of reflectometry sample environments across the world. This presentation will be followed by a discussion section on the limiting factors in developing new environments and how we can better collaborate on sample environments cross-facility.

Abstract: QIKR is envisioned as a general-purpose, horizontal-sample-surface neutron reflectometer [1]. The large instantaneous neutron flux and broad wavelength bandwidth of the SNS STS will routinely allow informationally complete specular reflectivity measurements to be carried out at a single instrument setting within seconds. This “cinematic” measurement capability will make accessible routine time-dependent characterization of interfacial structures over a broad range of scientific disciplines, including energy materials, polymers, and biological membranes. I will describe QIKR’s design, illustrate its capabilities, and discuss its prospects.
[1] J.F. Ankner, et al., Rev. Sci. Instrum. 94, 013302 (2023)

Abstract: SOFIA is a horizontal-type neutron reflectometer at Beamline 16 (BL16) at MLF, J-PARC. SOFIA provides an advantageous capability for investigating free surfaces (liquid–air and liquid–liquid interfaces), enabling measurements with the sample kept horizontal over the full Qz-range, and has therefore been widely utilized for interfacial studies, particularly in soft-matter science. Benefiting from the high neutron intensity at J-PARC and efficient use of TOF method, SOFIA enables neutron reflectometry (NR) with relatively short data acquisition times.
At a single incident angle, the accessible Qz-range is limited by the available wavelength band. SOFIA is therefore being upgraded to a multi-incident-angle neutron reflectometer (MI-NR) combined with focusing optics [1]. This system aims to cover a wide Qz-range simultaneously with enhanced neutron intensity at the sample, enabling efficient operando and time-resolved measurements. A proof-of-principle demonstration was performed using two detectors to acquire reflectivity profiles at two incident angles simultaneously. A 30-nm-thick deuterated polystyrene film was measured for 30 min at 100 kW, corresponding to approximately 3 min at 1 MW. Despite limited counting statistics, the experiment demonstrated the feasibility of MI-NR and covered a wide single-acquisition Qz-range of 0.1-3 nm^-1.
The first focusing mirrors caused beam broadening because of fabrication issues. New mirror pairs are currently under production, with the goal of completing the MI-NR installation and beginning user operation by the end of 2027.
[1] N. L. Yamada, et al., J. Appl. Crystallogr., 53 1462–1470 (2020)

Abstract: Thin films composed of soft matter often exhibit heterogeneities in composition and molecular orientation distributed throughout the film’s depth. This morphology can dramatically influence a material’s function such as chain orientation in semiconducting polymers that can introduce anisotropic optoelectronic properties. Characterizing such stratification is challenging as few experimental techniques simultaneously resolve depth-dependent composition and molecular orientation, particularly in semi-crystalline or amorphous materials. Resonant soft X-ray reflectivity (RSOXR) is an experimental technique that combines the chemical sensitivity of near-edge X-ray absorption fine structure (NEXAFS) spectroscopy with the depth-profiling capabilities of X-ray reflectivity. Soft X-rays leverage intrinsic chemical contrast near elemental absorption edges relevant for soft matter, including carbon (284 eV), nitrogen (410 eV), and oxygen (543 eV). The application of polarized X-rays extends this capability, providing sensitivity to the alignment of NEXAFS dipoles which directly relates to the orientation of molecules under investigation. This presentation will provide an overview of RSOXR capabilities and ongoing research for studying soft matter at the Advanced Light Source (ALS). Experimental requirements and data analysis strategies will be discussed, including differences from hard X-ray or neutron reflectivity. This will include a brief introduction to our current polarized reflectivity modeling software, pypxr, and future plans to develop a native hyperspectral modeling platform. Challenges for operating in this X-ray regime will be addressed alongside opportunities and use cases in soft matter research.

Abstract: The Liquids Reflectometer (LR) is a time-of-flight neutron reflectometer at the Spallation Neutron Source (SNS) with a horizontal sample geometry that enables neutron reflectometry measurements at free liquid interfaces. Commissioned 20 years ago, LR began serving the user community in 2007. This presentation will highlight instrument developments over the past five years, focusing on advances that allow measurements to be tailored to particular experiment needs and new capabilities for improving automation, data quality, and throughput.

Abstract: Neutron and X-ray reflectometry are powerful techniques for the study of interfacial systems and are in widespread use across the world. However, historically these techniques have suffered from the issues of reproducibility, repeatability and replicability seen across all of science. We would like to publish a white paper in the name of ORSO, we aim to establish best-practice for reporting the results of X-ray and neutron reflectometry experiments. We believe that this advice will help to improve the reproducibility of published reflectometry data and to direct the development of appropriate tools to facilitate this. We have drafted a paper that considers reproducibility in all aspects of the reflectometry experiment, including the sample, the sample environment, the measurement protocol, the data treatment pipeline and the data analysis process. The aim is to offer pragmatic and practical advice to all working in this field and we are now looking for contributors to help improve the paper and to ensure it truely reperesents a consensus of the ORSO community.

Abstract: This talk will cover a range of topics from the use of AI & Machine Learning as an analytical tool, through to an optimiser for high dimensional problems such as beamline alignment through to improvements for the user experience when acquiring data and how all of this can be linked by a series of latency based development platforms that Diamond is working on as part of its facility upgrade project Diamond-II.

Abstract: Soft matter research still waits on humans at every step of the cycle: writing and selecting proposals, running experiments and simulations, and analyzing the results. We built three large language model (LLM) agent systems, each aimed at one of these steps. ProposalArena tests whether LLM judge panels can rank beamtime and computing proposals. We score real historical proposals by individual grading and by pairwise comparison, then check the rankings against the publications each proposal later produced. ToPolyAgent runs polymer molecular dynamics with three cooperating agents, one each for system configuration, simulation, and reporting; from a single natural-language prompt it handles linear, ring, brush, star, and dendrimer topologies, in interactive or fully autonomous mode. SasAgent analyzes small-angle scattering data. It wraps SasView’s model library, SLD calculator, and fitting routines as callable tools, and retrieves from SasView documentation when choosing a model, taking raw I(q) to a converged fit for colloidal and polymer systems. Each agent removes a different wait from the cycle: for proposal reviewers, for simulation setup expertise, for scattering analysis experience. We see them as working pieces of an eventual autonomous research loop at user facilities.

Abstract: Artificial intelligence and machine learning are generating enormous interest across the physical sciences, but what can they realistically deliver for reflectometry? With potential applications ranging from real-time data analysis and experiment automation to large language models for user support and scientific workflows, this session will feature two invited talks highlighting recent developments and practical applications, followed by an open discussion on the opportunities, challenges and future role of AI/ML within the reflectometry community. The discussion will help inform ORSO’s future activities and priorities in this area.

Reports From the working groups not coverered earlier
Data Analysis Working Group: Brian Maranville
A short summary of progress on the Neutron Round Robin : Rebecca Anderson
File Formats Working Group: Max Skoda
Education and Outreach Working Group: Tom Arnold
Voting: Restructuring of ORSO? and election of chairs.
The results of the election: It was decided to creat a new working group covering AI. Tim Snow and Stefan Kowarik were elected as the chairs for this group. Rebecca Anderson was elected to E&O, Chen Shen to Data Formats, Hayden Robertson to Reproducibility, and David Walwark to Sample environment. Brian Maranville was reelected to the Data Analysis working group.