Techniques¶
What the modelled part of 8-ID is designed to do, as intent. First cut.
A technique is a portable Catalog Method; a Practice is how a facility adapts it. 8-ID's signature technique, XPCS, is now a catalog Method (cora.capability.xpcs): it is the second beamline after LCLS-MFX to need a DAQ-owned high-rate frame stream, which graduated XPCS out of the imaging-heritage catalog. Small-angle scattering and six-circle diffraction stay pending until they enter scope (TECH-1).
X-ray photon correlation spectroscopy¶
XPCS measures the time correlations of a coherent speckle pattern to probe sample dynamics, so it records long, fast time series on an area detector under a precisely gated exposure.
| Technique | Catalog method | Notes |
|---|---|---|
| XPCS | xpcs |
coherent-scattering intensity time series on the Eiger / Lambda / Rigaku detectors, gated by the softGlue timing; now a catalog Method. Its acquisition is a DAQ-owned high-rate frame stream with no executing body yet, the event-stream acquisition axis (Stage 1) |
| Small-angle scattering | small_angle_scattering |
static SAXS on the same detectors; a Plan setting over the same chain |
Both need the XPCS sample stage, the coherent detectors, and the flight path. The fast shutter and softGlue timing (XPCS-1, XPCS-3) gate the exposure.
Six-circle diffraction¶
The 8-ID-E Huber diffractometer orients a single crystal through six circles and scans reciprocal space, sharing the diffraction Method with 4-ID.
| Technique | Catalog method | Notes |
|---|---|---|
| Six-circle diffraction | diffraction |
reciprocal-space scans on the six-circle Huber; shares the 4-ID diffraction Method (TECH-1) |
It needs the diffractometer. The reciprocal-space coordination is DIFF-2; the reusable Assembly(Diffractometer) is on Model.
Not modelled yet¶
The XPCS Method now exists, but the concrete acquisition primitive that executes it (a DAQ-owned high-rate frame stream, not a poll-to-Done capture) does not: that is the event-stream acquisition axis, now at Stage 1 (8-ID XPCS is its second beamline after LCLS-MFX). Small-angle scattering and diffraction Methods remain an owner-scope decision (TECH-1); see Open questions for the world-facts to confirm first.