Techniques¶
What ISR is designed to do, as intent. A deliberately partial first cut.
A technique is a portable Catalog Method; a Practice is how a facility adapts it. ISR's mission is hard X-ray resonant scattering and surface / interface diffraction, with in-situ sample environments. The Methods below render unlinked and are doubly deferred: the Methods themselves are pending, and the multi-circle diffractometer they run on is absent from the source (TECH-1, DIFF-1).
| Technique | Catalog method | Notes |
|---|---|---|
| Resonant scattering | resonant_scattering |
resonant elastic scattering near an absorption edge; reuses the Method APS 4-ID (POLAR) and CSX left pending; needs a tunable energy axis and a diffractometer, both absent from source (TECH-1, RESONANT-1, DIFF-1) |
| Surface / interface diffraction | diffraction |
crystal truncation rods and surface structure; reuses the diffraction Method 4-ID / 8-ID left pending; needs the multi-circle diffractometer, absent from source (TECH-1, DIFF-1) |
Both techniques would need the incident-beam chain (the undulator, the DCM for energy, the focusing mirrors, the attenuator), a multi-circle sample diffractometer, and the Eiger area detector. The first two of those are partly modelled; the diffractometer is not.
Reuse, not new vocabulary¶
ISR coins no new Method. Its resonant scattering reuses the resonant_scattering Method that APS 4-ID POLAR brought and CSX shares; its surface / CTR diffraction reuses the diffraction Method that 4-ID / 8-ID share. So ISR adds, when it lands, further consumers of two pending Methods, strengthening the case for cataloging them, but it does not mint vocabulary. The matching Site Practices (ISR_resonant_scattering_practice, ISR_surface_diffraction_practice) are carried pending in the NSLS-II Site.
Why these are doubly deferred¶
For every other beamline the technique Methods are deferred because the Capability is not yet in the catalog (the owner-scope decision). At ISR there is a second, harder deferral: the devices the techniques run on are not in the public source. Resonant scattering needs a tunable energy axis (a non-functional stub here, RESONANT-1) and surface diffraction needs a multi-circle diffractometer (only two axes bound, DIFF-1). So these Practices are intent recorded against a partial scaffold, not a capability CORA could drive today. They firm up as the diffractometer and the energy axis enter the source.
Not modelled yet¶
The concrete acquisition recipes are not written yet, and cannot be until the diffractometer lands: the reciprocal-space (hkl) scans, the rocking-curve and CTR trajectories, the energy scans across an edge for resonant work, and the in-situ environment programs. The integration and reduction (azimuthal / CTR rod integration) are ComputePort work, not beamline Methods. These join as ISR's profile collection grows past its current optics-first state.
See Open questions for the world-facts to confirm first, especially the diffractometer (DIFF-1) and the in-situ environment (INSITU-1).