ISR

The In Situ and Resonant beamline at NSLS-II, beamline 4-ID: hard X-ray resonant elastic / inelastic scattering near absorption edges, surface and interface diffraction (crystal truncation rods), and in-situ sample environments. This page walks the operational core CORA models today. It is a reverse-engineered, and deliberately partial, first cut: the public source is an early, optics-first profile collection.

Property	Value
Asset	ISR (root Asset, tier = Unit, parent_id = None)
Facility	NSLS-II (bound via facility_code = "nsls2", FacilityKind = Site)
Sector	Sector 4 (PV namespace XF:04ID*; not a registered Asset)
Status	First cut, reverse-engineered, design-phase, partial (optics + detector + two end-station axes; the diffractometer is deferred)
Source	An in-vacuum undulator (read-only gap in source) (SRC-1)
Control stack	NSLS-II EPICS / ophyd, bluesky-queueserver + Tiled; handles bound from the profile collection, carried confirm (CTRL-1)

First cut, partial, and confirm-pending by intent

This scaffold was reverse-engineered from the beamline's own bluesky profile collection (NSLS2/isr-profile-collection), which is an early / commissioning, optics-and-detectors-first scaffold. EPICS PVs are real and read from the startup/ files; the devices that ISR's name implies (the multi-circle diffractometer, the in-situ sample environment, a wired resonant energy axis, polarization analysis) are absent or stubbed in the source and are carried as open questions, not invented. Every modelled value is carried as confirm until ISR staff verify it. What CORA needs the team to confirm is on Open questions.

What ISR is, and what the source actually contains

ISR's mission is hard X-ray in-situ and resonant studies: resonant scattering near absorption edges, surface and interface diffraction (crystal truncation rods), and in-situ environments (electrochemistry, gas, temperature). That mission needs a multi-circle diffractometer, a tunable resonant energy axis, in-situ sample cells, and often polarization analysis.

The honest finding, and the reason this is a partial cut, is that the public profile collection does not yet contain those mission devices. What it binds is an optics-and-detectors-first scaffold:

• the front-end slit, the in-vacuum undulator gap (read-only), the double-crystal monochromator, the bendable focusing mirror pair, and the harmonic-rejection mirror;
• the four-foil attenuator bank;
• the Eiger 1M area detector and the diagnostic screen cameras;
• and, of the diffractometer, only two bound axes (a sample rotation th and a second axis zeta, under the Dif:ISD diffractometer IOC).

The multi-circle diffractometer (its orientation circles, its detector two-theta arm, its reciprocal-space engine), the in-situ sample environment, a wired resonant energy axis, and polarization analysis are all absent or stubbed (the flux-monitor electrometers are even commented out, and the energy axis is a non-functional stub). So CORA models what is PV-bound and routes the four mission-critical gaps to Open questions, the same discipline the i20-1 (EDE) partial follows.

ISR coins no new Family and changes nothing in the catalog. Its science would reuse the existing pending resonant_scattering Method (APS 4-ID, CSX) and diffraction Method (4-ID / 8-ID); both are deferred, and doubly so here because the diffractometer they run on is not yet in source.

Scope: what is and is not modelled

Part	In this cut	Why
Optics (FE:C04A, XF:04IDA-OP, XF:04IDB-OP)	Yes	The undulator gap, the DCM, the focusing pair, the harmonic-rejection mirror, the front-end slit (ENC-1)
Endstation (XF:04IDD-ES)	Yes (partial)	The filter bank, the two bound sample axes (th, zeta), the Eiger 1M (ENC-1)
New device classes	None	Zero new Families coined; nothing graduates; the catalog is unchanged
The multi-circle diffractometer	No (absent in source)	Only th + zeta are bound; the orientation circles, detector arm, and reciprocal-space engine are an open question (DIFF-1)
The in-situ sample environment	No (absent in source)	No temperature / electrochemistry / gas / cryostat device is PV-bound (INSITU-1)
The resonant energy axis + polarization	No (stubbed / absent)	The energy axis is a non-functional stub; no polarization analyzer or phase retarder is bound (RESONANT-1)
The flux monitors	No (commented out)	The QuadEM electrometers are defined but commented out in source (DET-1)
Integration scenarios + vendor Models	No	Design-phase; the descriptor and docs come first

The deferred parts are recorded on Model.

Key modelling decisions

• ISR is a deliberately partial scaffold. CORA models the PV-bound optics + Eiger + the two bound end-station axes, and routes the absent mission devices (diffractometer, in-situ environment, resonant energy axis, polarization) to open questions rather than inventing them (DIFF-1, INSITU-1, RESONANT-1).
• The single bound sample rotation binds RotaryStage, not Goniometer. Only th + zeta are bound under the Dif:ISD IOC; with no detector arm and no reciprocal-space engine there is no basis to scaffold a multi-circle Goniometer, so it is one RotaryStage Asset with the full diffractometer deferred (DIFF-1).
• 4-ID is an undulator beamline. The in-vacuum undulator is observed (read-only gap in source) alongside the loose StorageRing; the device detail is SRC-1.
• The optics reuse the catalog. The DCM binds Monochromator; the bendable focusing pair and the harmonic-rejection mirror bind Mirror; the front-end slit binds Slit; the filter bank binds Filter.
• The Eiger and screen cameras bind Camera; the motorized BPM stage binds the loose BeamPositionMonitor. The flux-monitor electrometers are commented out in source, so no FluxMonitor Asset is modelled (DET-1, DIAG-1).
• Zero new Families coined, no new Method slugs, nothing graduates, the catalog is unchanged.

The beamline

• Source: the generated device walk: the storage-ring machine state, the in-vacuum undulator gap, the double-crystal monochromator, the bendable focusing pair and the harmonic-rejection mirror, the front-end slit, and the attenuator bank.
• Sample: the two bound end-station axes (th / zeta), and where the absent multi-circle diffractometer and in-situ environment sit.
• Detector: the Eiger 1M area detector, the diagnostic screen cameras, the motorized beam-position monitor, and the commented-out flux monitors.

Cutting across them:

• Controls: the EPICS / ophyd control stack, the early-commissioning signals, and the absent mission devices; handles bound from the profile collection and carried confirm (CTRL-1).

The cross-cutting reference view is the Inventory. The Source page is generated from the beamline.yaml descriptor.

Techniques

Techniques: what ISR is designed to do, as intent. Resonant scattering maps to the pending resonant_scattering Method (shares 4-ID / CSX) and surface / CTR diffraction to the pending diffraction Method (shares 4-ID / 8-ID). Both render unlinked and are doubly deferred: the Methods are pending and the diffractometer they run on is absent from source (TECH-1, DIFF-1).

Governance

Governance: who will act at ISR and the trust shape that gates their commands. People and autonomous agents are facility principals at the NSLS-II Site, surfacing through their actions and gated by a Zone-plus-Conduit-plus-Policy trust shape. The NSLS-II operator pool and review are pending at the Site (GOV-1). No PSS / photon-shutter / hutch-interlock device is in the profile collection, so the permit signals are carried pending, not invented (PSS-1).

Model

Model: the developer's by-kind index into where each CORA aggregate's ISR content lives, and the record of what is deliberately deferred. ISR introduces no new Family.

Not yet documented

ISR is not yet driven by CORA, and its source is an early partial, so the operations runbook and the live experiment view are deliberately not written yet. They join as the diffractometer and in-situ environment enter the source and the deployment firms up. The 2-BM deployment shows the shape they will take. The PSS permit signals and the absent mission devices are not invented here (PSS-1, DIFF-1, INSITU-1, RESONANT-1).