Operando4NeXus – Standardisation of Operando Data and Metadata for NeXus

A critical gap in scientific data management is addressed by Operando4NeXus through the development of a standardised approach for storing Sample Environment (SE) and lab-based experimental data within the NeXus format. Despite being an international standard for neutron, x-ray, and muon data, NeXus lacks comprehensive methods for representing complex operando sample environments and laboratory data consistently across facilities. Modern operando setups are often modular and mobile, moving between laboratory and beamline environments. They generate time-dependent, multi-parameter records of the sample state (e.g., temperature, pressure, gas composition, electrochemical potentials) that are essential for reproducibility and reuse.

Taking into account the results of the SECoP@HMC and the issues pertaining to data storage that have emerged during the course of the ROCK-IT project. Operando4NeXus will align with the efforts of related initiatives (e.g., FAIRmat, DAPHNE4NFDI) and generalise the approach beyond strict protocol mapping and define standards for storing sample-environment, laboratory, and operando data and metadata.

The project’s objectives are to:

• (1) develop a unified standard for storing sample-environment data and metadata in NeXus that ensures seamless compatibility between beamline experiments and laboratory-based/offline measurements;

• (2) enhance data interoperability and reusability through comprehensive metadata schemas that capture the full complexity of experimental conditions across research environments;

• (3) enable linking to external knowledge bases (e.g., controlled vocabularies/ontologies) to support semantic interoperability.

Community alignment and sustainability are central: partners from multiple Helmholtz centres and international facilities will work closely with the NeXus International Advisory Committee (NIAC) and NFDI initiatives such as DAPHNE4NFDI and FAIRmat to ensure that the resulting definitions are broadly usable and widely accepted by the scientific community.