Techniques

What the modelled part of CMS is designed to do, as intent. First cut.

A technique is a portable Catalog Method; a Practice is how a facility adapts it. CMS measures soft-matter and thin-film structure four ways: small-, wide-, and medium-angle scattering (SAXS / WAXS / MAXS), grazing-incidence scattering (GISAXS / GIWAXS), and specular X-ray reflectivity (XR). Three of those four are scattering the fleet already speaks; the Methods below render unlinked and are carried pending until the owner-scope decision (TECH-1) brings any of them into the catalog.

CMS is the NSLS-II twin of SMI (12-ID), and most of what it does reinforces vocabulary CORA already holds. Read this page for the one technique that is genuinely distinct: specular reflectivity.

Technique	Catalog method	Notes
Small-angle scattering (SAXS)	small_angle_scattering	low-Q on the SAXS Pilatus 2M; shares the science axis with i22 and SMI; Method not yet in catalog (TECH-1)
Wide- and medium-angle scattering (WAXS / MAXS)	wide_angle_scattering	wider-Q on the Pilatus 800K heads, one powered per configuration; shares the axis with i22; Method not yet in catalog (TECH-1)
Grazing-incidence scattering (GISAXS / GIWAXS)	grazing_incidence_scattering	the same scattering with the sample at a grazing angle on sth; shares the axis with APS 9-ID and its NSLS-II twin SMI; Method not yet in catalog (TECH-1)
Specular X-ray reflectivity (XR)	reflectivity	step sth, slide a detector region-of-interest in lockstep across the fixed Pilatus 2M, integrate the specular intensity; the second consumer of the reflectivity Method after i10 (XR-1, TECH-1)

All four techniques need the incident-beam chain (the DMM for energy, the mirrors, slits, and absorber foils), the sample stack (the Goniometer, surface-leveling tilts, temperature stage), and the endstation detectors (the Pilatus heads, beamstop, flux monitors). Scattering reads an area frame at one orientation; reflectivity reads the same area detector while the orientation is stepped.

The scattering is reinforcement, not novelty

SAXS, WAXS, MAXS, and grazing-incidence scattering overlap the fleet heavily. CMS is the direct NSLS-II twin of SMI, and the two share their science axis with Diamond i22 and APS 9-ID / 12-ID-E: the same Camera / Goniometer / Slit / BeamStop / FluxMonitor vocabulary, zero new families, the same pending scattering Method slugs. MAXS is a detector-position variant of wide-angle scattering on a second Pilatus 800K head, not a technique of its own. GISAXS / GIWAXS is the same scattering with the sample tipped to a grazing angle on sth, a sample-orientation variant rather than a new Capability.

So the scattering side of CMS earns no new abstraction. It reinforces, at a second NSLS-II beamline, the case that the small- and wide-angle scattering Capabilities belong in the catalog (TECH-1), the same earn-the-abstraction discipline SMI and i22 already follow. The device Roles exist (the Pilatus heads present Detector, the flux monitors present Sensor), so what stays pending is the science Capability, not a device shape. Because those Capabilities are not yet in the catalog, the matching Site Practices (CMS_small_angle_scattering_practice, CMS_wide_angle_scattering_practice, CMS_grazing_incidence_scattering_practice) are carried pending in the NSLS-II Site; each binding lands when its Capability does.

Specular reflectivity, the distinct contribution

Specular X-ray reflectivity is the one technique CMS brings that the scattering vocabulary does not cover, and CORA models it as a Method over existing devices, coining no hardware.

There is no physical two-theta detector arm at CMS, and no point detector. The area detector stays fixed. The measurement steps the sample incidence angle sth (the same grazing-incidence angle the GISAXS Method uses) and, in lockstep, slides a software region-of-interest across the face of the fixed Pilatus 2M to where the specularly reflected beam lands at each angle. The intensity inside that tracked region is integrated; the angle the region sits at is a synthetic two-theta computed from the geometry, not a value read off a moving arm. The result is the reflectivity curve: specular intensity versus angle, with the incident flux read on the endstation flux monitor to normalize.

Reuses	Role in XR
Goniometer (sth)	steps the specular incidence angle
Pilatus 2M Camera	read over a tracked region-of-interest; the synthetic two-theta is where that region sits
endstation FluxMonitor	incident flux, for normalization

That is the whole device list. XR coins no two-theta arm, no point detector, no new family. The reflectivity Method is the same one i10 brought to CORA at its soft X-ray sibling, where the geometry is realized differently; CMS is the second consumer of the Method (XR-1), realizing it in the hard X-ray regime with no new hardware. As with the scattering Capabilities, the Method is not yet in the catalog and CMS_reflectivity_practice is carried pending (TECH-1, XR-1).

Not modelled yet

The concrete acquisition recipes are not written yet. For scattering that is the per-frame exposures, detector distances, beamstop placement, and the azimuthal integration that turns 2D frames into I(Q) curves (the integration and reduction are ComputePort work, not beamline Methods). For reflectivity it is the sth step list, the region-of-interest tracking model that maps each angle to its place on the fixed Pilatus, and the synthetic two-theta calibration. These join as the deployment approaches the point where CORA drives CMS.

Whether any of these four techniques enters CORA's catalog is an owner-scope decision on Model: a modelling exercise reinforces the case but does not mint cross-facility Method vocabulary on its own. The scattering Capabilities are shared pending slugs the fleet already debates; what CMS adds is a second consumer of the pending reflectivity Method (i10 plus CMS), which strengthens the case for cataloging it but leaves that an owner decision, not an automatic one (XR-1, TECH-1). See Open questions for the world-facts to confirm first.