Techniques¶
What CORA would run at ISS: X-ray absorption and X-ray emission spectroscopy, each a Catalog Method. ISS follows the deferral discipline of the beamlines that brought spectroscopy to CORA.
ISS's measurement is energy spectroscopy: it sweeps the incident energy across an absorption edge (EXAFS) and, with the crystal emission spectrometers, resolves the emitted spectrum (XES) or selects an emission line during the incident-energy sweep (HERFD). The Methods below render unlinked and are carried pending until the owner-scope decision (TECH-1) brings them into the catalog.
| Technique | Mode | Notes |
|---|---|---|
| X-ray absorption (EXAFS) | transmission / fluorescence, energy fly-scan | I0 / It / Ir ion chambers or the Xspress3 SDD over a trajectory energy sweep; the BMM energy-scan question (ENERGY-1, TECH-1) |
| X-ray emission (XES) | emission spectrometer, fixed incident energy | the Johann or von Hamos crystal spectrometer disperses the emitted spectrum onto the area detector (SPEC-1, TECH-1) |
| HERFD | emission spectrometer, incident-energy fly-scan | high-energy-resolution fluorescence detection: scan the incident energy, read one emission line through the analyzer (ENERGY-1, SPEC-1) |
All three need the sample stage and a detector; the trajectory fly-scan sweeps the energy and the analog pizza box reads the detectors synchronously.
Why the Method scope stays pending¶
ISS's absorption and emission both lean on energy spectroscopy CORA carries pending. EXAFS is the energy-sweep-as-the-measurement case BMM raised: the energy_scan Capability is anticipated in the catalog but deferred until a conduct-path forces it (ENERGY-1), and a descriptor scaffold does not force it; ISS is a further consumer that strengthens the case without coining it. The emission techniques (XES, HERFD) are the same shape LCLS-MFX left pending as the xas_spectroscopy Method (XAS / XES via the emission spectrometer), so ISS reuses that Method as the second consumer rather than coining a new one (TECH-1), and records that one pending Practice on the NSLS-II Site. The device Roles already exist (the ion chambers present Sensor, the SDD the energy-dispersive Sensor, the emission spectrometers the Detector Role); what is new is the science Method, not a device shape.
The per-technique reduction (EXAFS normalization and fitting, XES / HERFD spectra) is ComputePort work, not beamline Methods.