Proposal: Njord & Remora
Executive Summary
Njord and Remora are presented as a paired instrument concept for the European Spallation Source: one instrument tuned for ambitious small-sample science, and a second, symbiotic spectrometer designed to increase user capacity. Together they aim to unlock measurements that are currently out of reach for cold neutron spectroscopy, especially for materials with very small crystals, weak signals, or demanding sample environments.
The proposal focuses on two linked problems: important science cases are being limited by neutron flux and sample geometry, and the community also needs more beamtime. Njord addresses the first by pushing the available brightness into a tightly focused beam, while Remora uses the remaining spectral window to add a complementary direct-geometry spectrometer on the same beamport.
Background
Many of the most interesting neutron-scattering subjects are also the hardest to study. Metal-organic frameworks, organic superconductors, quantum magnets, pressure-tuned materials, are systems where the relevant signals are weak, the samples are tiny, or the experiments need extreme sample environments such as pressure cells and large-field cryomagnets.
Existing instruments often run into practical limits before the science is exhausted. For some questions the samples are simply too small; for others, the signal is buried in background or the required measurement time becomes prohibitive. This as both a scientific opportunity and a capacity challenge for the European neutron community.
Proposed Solution
Njord is the high-flux, small-sample instrument in the pair. It is designed to concentrate intensity into a very small beam spot, enabling dynamic studies on millimeter-scale samples and improving access to difficult measurements in pressure cells, magnet systems, and other restrictive environments. Njord’s wide analyzer coverage and ability to capture rich momentum and energy information even when the sample volume is limited will enable new science.
Remora complements Njord rather than competing with it. Using part of the long ESS pulse not accepted by Njord, it functions as a compact direct-geometry spectrometer with multiplexing in mind. In practical terms, that means a second scientific output stream from the same beamport, giving ESS both more capability and more throughput.
Expected Impact
The combination of Njord and Remora will broaden ESS science in two ways. First, it will open measurements on classes of materials that are currently difficult or impossible to study with neutrons, including flexible framework materials, organic superconductors, and quantum magnets under pressure. Second, it will help relieve the persistent demand for beamtime by adding a new spectrometer that supports a wider user base and training pipeline.
That dual impact is central to the concept: Njord pushes the frontier of what can be measured, while Remora helps ensure those measurements are accessible, sustainable, and useful to a broader community.
Conclusion
Njord and Remora are best understood as a symbiotic proposal: one instrument maximizes scientific reach on small and challenging samples, and the other expands capacity and access. They are a strategic fit for ESS, aligned with the long-pulse source and the facility’s role as a leading neutron center in Europe.
This post summarizes the main themes from the proposal. A downloadable PDF version will be linked here once the proposal is finalized.
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The finalized proposal PDF will be made available for download here once it is ready.