Controls¶
The control stack and the orchestration seam. Design-phase, with the dodal-derived handles recorded.
i10 runs the Diamond EPICS control stack driven through ophyd-async, the same floor as I22, I03, I15-1, I11, I24, and i06. CORA observes that floor and, where it replaces bluesky-style orchestration, conducts over it; it does not replace EPICS. As at the other Diamond beamlines, the control handles are known: Diamond's open dodal library records the real EPICS PV root for each device, so this scaffold carries a handle on every Asset. i10 is the fleet's second APPLE-II source after i06, and its soft X-ray twin, so the source-side control story below is the i06 posture reused, not a new one.
Device handles¶
CORA models each device's control handle as an opaque string set at the edge. For i10 the EPICS PV roots are read from dodal (the src/dodal/beamlines/i10.py, i10_shared.py, and i10_1.py factories and the src/dodal/devices/ classes) and carried confirm, because a controls-library snapshot is not a guarantee against the live system (CTRL-1). The handles follow the Diamond convention, a PV root that encodes a functional zone rather than a hutch. The zones i10 spans:
| PV zone | Carries | Example roots |
|---|---|---|
BL10I |
the optics spine: the PGM, the collimating / switching / focusing mirrors, the optics slits | BL10I-OP-PGM-01:, BL10I-OP-SWTCH-01:, BL10I-OP-COL-01: |
SR10I |
the APPLE-II servo crates that drive the undulator gaps | SR10I-MO-SERVC-01: (downstream IDD), SR10I-MO-SERVC-21: (upstream IDU) |
ME01D |
the i10-rasor endstation: the diffractometer, the analyzer arm, the cryostat sample stage, the detector channels | ME01D-MO-DIFF-01:, ME01D-MO-POLAN-01:, ME01D-MO-CRYO-01: |
BL10J |
the i10-1 / I10J magnet endstation: the electromagnet and superconducting magnet, the magnet stages and optics | BL10J-EA-MAGC-01:, BL10J-EA-SMC-01: |
The full handle list, Asset by Asset, is in the Inventory, and the source walk that binds each one is the generated Source page.
What dodal does not give, and so is not invented: which access-gated enclosure each zone maps to (the PV encodes a functional zone, not a hutch or its safety meaning, ENC-1), and the calibrated values behind the handles.
The APPLE-II controller seam¶
i10 is CORA's second APPLE-II source after i06, so its run drives the X-ray polarization as an experiment axis (linear horizontal LH / vertical LV, circular positive PC / negative NC, linear-arbitrary LA, plus third-harmonic variants) alongside the incident-energy axis. Both are modelled as PseudoAxis Assets over the source, reusing the i06 precedent rather than coining anything new. The continuous linear-arbitrary angle is the continuous realization of the LA value within the same polarization axis, not a second axis and not a new Family.
The seam to record is that the geometry already lives below CORA. An APPLE-II chooses its polarization by driving its magnetic phase rows, and the live i10 controller holds the energy-to-gap polynomial and the polarization-to-phase conversion for both undulators (the downstream IDD on SR10I-MO-SERVC-01: and the upstream IDU on SR10I-MO-SERVC-21:). By default that edge controller owns the kinematics:
- CORA names the energy and polarization pseudo-axes, writes the requested value, and records the move.
- The live i10 controller converts the value into gap and phase-row positions and drives the servo crates.
So the polarization pseudo-axis is carried rule-less (POL-1): the polarization value domain is the axis's value set, but its partition rule lives in the edge controller, not in a CORA Calibration. This is the "edge IOC already computes the geometry" seam, the same posture the energy axis takes over the PGM and the APPLE-II gap (MONO-1). Pinning the conversion as a CORA-owned Calibration is a deferred decision, needed only if CORA must scan polarization without the i10 controller in the loop (POL-1). Both undulators are driven sources; whether the incident-energy axis wires over one gap or two is the question carried as ENERGY-1.
The orchestration seam¶
Three sequence families run as bluesky plans over ophyd-async / EPICS today, and that is the seam a CORA edge replaces, conducting over the same floor (i10-1):
- Resonant scattering and reflectivity scans (RASOR). The
ME01D-MO-DIFF-01:diffractometer scan over the two-theta scattering arm and the sample circles (DIFF-1), coordinated by the reciprocal-space pseudo-axis (DIFF-2), with reflectivity the R in RASOR. CORA's edge would conduct that sequence over the goniometer circles and the source axes rather than EPICS owning the loop. - Polarization-analysis sequences. The analyzer arm (the PaStage / POLAN arm,
ME01D-MO-POLAN-01:) is driven to select the scattered-beam polarization channel alongside the diffractometer move. dodal exposes the arm's motors only; the sequence over those motors is the seam, with no analyzer-crystal specifics invented (POL-2). - Applied-field dichroism sequences and field sweeps. The i10-1 / I10J XMCD / XMLD acquisition over the electromagnet (
BL10J-EA-MAGC-01:, set-and-read) and the superconducting magnet (BL10J-EA-SMC-01:, a flyable field sweep), with the sample at low temperature. The plan steps energy and polarization at an absorption edge while setting or sweeping the field; CORA's edge would conduct that sequence over the source axes and the magnet rather than EPICS owning the loop (MAG-1).
In each case EPICS stays the floor and CORA's edge replaces the bluesky-style orchestration, driving through ophyd-async. None of this is built yet; it is the recorded seam for the eventual conducting work, and the Methods behind these sequences (resonant scattering, reflectivity, XMCD, XMLD) are carried pending (see Model).
Equipment protection¶
The PSS search-and-secure permit signals, the photon and front-end shutters, and any interlock tier are absent from dodal and are not invented here (PSS-1). dodal is a device-control library, not a safety-system description: it carries the motion and optics handles, not the permit leaves behind an interlocked enclosure. CORA names neither a permit signal nor a shutter for i10 until the beamline team supplies them.
i10 also carries hazard classes that are governed at the Site, not modelled here: a soft X-ray UHV beamline with an intense polarized beam, high magnetic fields (a superconducting magnet at i10-1), and cryogenics. The Enclosure permit shape and the hazard tier are carried pending at the Diamond Site; the governance and safety envelope follow the 2-BM shape (see Governance and the safety envelope).
Detection: point detectors, no area detector¶
i10 has no area detector at either endstation (DET-1). The science detection is point and current-integrating, so the science detector binds the catalog FluxMonitor Family rather than a camera or pixel-array detector, and none is invented in the meantime:
- RASOR point detection (
ME01D). The scattered-beam point detector on scaler channel S18, the incident-flux monitor on S17, fluorescence on S19, and the drain-current / total-electron-yield channel on S20, read through Femto / SR570 current amplifiers (DET-1). - i10-1 / I10J point detection (
BL10J). The TEY / FY / diode / monitor channels, again with no area detector behind them (DET-1).
Because there is no area detector, there is no pixel-array file-writing seam to model; the point channels are the science signal. See Open questions for the control, detection, and safety items still to confirm, and Model for the deferred Method decisions and the held-under-review Families (the loose PolarizationAnalyzer on the POLAN arm, POL-2, and the loose Magnet shared by both magnet devices, MAG-1).