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The software-triggered acquisition, the motion controllers, and the seam between CORA and the floor.

Triggering: software-gated acquisition

XPD does not use a hardware position-capture box. Its area detectors run in continuous or multi-trigger mode, gated by the endstation exposure shutter (ExposureShutter, XF:28IDC-ES:1{Sh:Exp}); a fast rapid-acquisition PDF measurement is a burst of detector frames over a held exposure. The exact acquisition modes are part of the recipe layer (deferred at this design phase).

Motion controllers

The diffractometer, sample, and detector stages are driven by endstation and optics motion controllers whose box models, firmware, and IPs are not in the profile collection (DRIVE-1), so EndstationMotionController is carried as a MotionController family with the specifics blank.

The seam: CORA and the floor

This is where CORA's design meets the XPD floor. The shape matches the other NSLS-II beamlines'.

CORA owns (its conducting engine, over the ControlPort):

  • the acquisition: stepping or ramping the sample environment, positioning the detector distance, and collecting the flat-panel frames under the gated exposure;
  • the choice of technique, detector, distance, and sample-environment program, gated by the trust boundary.

CORA drives through (the floor it actuates and observes, and does not replace):

  • the EPICS IOCs via the ophyd hardware abstraction: the ControlPort boundary;
  • the double-Laue and high-resolution mono drives, the mirror bender, the cryostream / furnace controllers, the PSS interlock, and the detector IOCs;
  • the facility filestore where the per-run frames land. CORA moves them, over the TransferPort, into CORA's own Dataset of record.

So CORA brings one conducting engine to XPD, working over the ports: powder / PDF acquisition over the ControlPort, the azimuthal integration and pair-distribution-function reduction over the ComputePort, and data egress over the TransferPort into the CORA Dataset. The integration and PDF reduction are a clean ComputePort leg, the powder-diffraction analogue of the reconstruction legs at the imaging beamlines.

The software IOCs (PerkinElmer, Dexela, QuadEM, Cryostream, Lakeshore, Linkam, the sample robot) are referenced by PV namespace only, never registered as Assets.