Sample¶

The i19 sample side, in EH2. Design-phase scaffold; values are reverse-engineered from dodal or inferred, and every uncertain one carries its question id.

The sample side is where i19 does chemical crystallography: the Newport kappa four-circle that orients a single crystal, the serial / microfocus fixed-target arm beside it, the MAPT microfocus aperture that defines the beam onto the sample, and the on-axis viewing cameras that centre a pin. It sits in the EH2 experiment hutch (i19-2); which hutch holds the four-circle is itself a confirmation (ENC-1), and the descriptor places it in EH2. This is the page where the most natural temptation, to coin a four-circle Family, is the wrong move, and the why-no-new-family note below says why.

The four-circle (plain Goniometer reuse)¶

Device	Family	Control handle	Notes
`Diffractometer`	`Goniometer`	`BL19I-MO-CIRC-02:`	the Newport kappa four-circle sample circles: phi / omega / kappa, with sample-centring on `BL19I-MO-SAMP-02` (DIFF-1)
`ReciprocalSpace`	`PseudoAxis`	(derived)	reciprocal-space axis driven over the four-circle, named-not-built (DIFF-2)

The kappa four-circle is catalog Goniometer reuse, not a new Family. The catalog Goniometer note states that chi-versus-kappa and axis count are a per-Asset setting, not a Family split, so the phi / omega / kappa sample circles bind Goniometer exactly as the i03 Smargon and the MX3 mini-kappa do; kappa is the setting (DIFF-1). The larger four-circle, the sample circles plus the 2theta detector arm plus det_z plus the reciprocal-space axis, composes the catalog Assembly(Diffractometer), the 4-ID / 8-ID / i06-1 pattern, named, not built in descriptor mode (DIFF-1). The 2theta arm folds as a RotaryStage slot of that Assembly and det_z as a per-Asset axis on the arm (the i06-1 precedent); the reciprocal-space partition rule is carried pending (DIFF-2). The real dodal sample-centring and circle motors are the controls-layer realization, not separate spine Assets.

Single-crystal diffraction here reuses the pending diffraction Method that 4-ID, 8-ID, and CSX already share; chemical-versus-magnetic single crystal is a Practice-level science difference, not a new Method (TECH-1).

The serial / microfocus arm¶

Device	Family	Control handle	Notes
`SerialStage`	`Goniometer`	`BL19I-MO-SRL-01:`	the serial / microfocus fixed-target arm: x / y / z / phi (SERIAL-1)

Beside the four-circle, the fixed-target arm binds a second Goniometer: x / y / z translation plus a phi rotation is the same role-noun, again with axis count as a per-Asset setting. The raster sub-mode, the grid-style scan a fixed-target serial collection drives across the mounted chip, would touch a grid-scan-style Method the catalog does not yet carry, so it is carried as a note, not modelled (SERIAL-1).

The microfocus aperture¶

Device	Family	Control handle	Notes
`Aperture`	`Aperture`	`BL19I-MO-PIN-01:` + `BL19I-MO-COL-01:`	the MAPT pinhole plus collimator microfocus aperture; sizes from config table `BL19I-OP-PCOL-01:CONFIG` (APERTURE-1)

The MAPT pinhole and collimator are the consumer-facing beam-defining Asset onto the sample, and they bind the catalog Aperture, following the i03 MAPT precedent (APERTURE-1). It composes the pinhole and collimator XY stages, and the selectable aperture sizes are a Capability settings schema read from the configuration table. The discriminator tension, that the catalog Aperture describes a fixed code pattern while the MAPT is a driven, size-selectable opening, is carried as APERTURE-1; the i03 sibling runs the same controls stack and the same MAPT and already binds Aperture, so i19 follows it. No aperture sizes are invented here; they are read from BL19I-OP-PCOL-01:CONFIG pending confirmation (APERTURE-1).

The viewing cameras¶

Device	Family	Control handle	Notes
`SampleViewerOnAxis`	`Camera`	`BL19I-EA-OAV-01:`	the on-axis OAV viewing camera (in EH1, `i19-1`) (DET-1)
`SampleViewerDiagonal`	`Camera`	`BL19I-EA-OAV-02:`	the diagonal OAV viewing camera (in EH1, `i19-1`) (DET-1)
`Backlight`	`Backlight` (loose)	`BL19I-EA-IOC-12:`	sample backlight in / out; fourth sighting, held under review (DET-1)

The OAV viewing cameras bind Camera. The thing that makes them interesting, pin-tip recognition for centring, is a Method behaviour, not a device: the image-recognition step that finds the crystal pin and drives the goniometer to centre it lives on the Camera as behaviour, so it adds no Family and no Asset (DET-1). The sample backlight reuses the loose Backlight Family, its fourth sighting after i03, i24, and fmx; the Family stays held under review (the illumination-affordance fold-versus-promote question), so i19 adds a sighting, not a new Family (DET-1).

Why no new family here¶

The four-circle is the page's whole modelling argument. A kappa four-circle goniometer is the kind of instrument that tempts a new FourCircle or Diffractometer Family, and i19 deliberately does not coin one:

The circles are a Goniometer. The catalog Goniometer note already settles that chi-versus-kappa and axis count are a per-Asset setting, not a Family split. kappa is a setting. The phi / omega / kappa sample circles bind Goniometer (DIFF-1), the same as the i03 Smargon and the MX3 mini-kappa, and the serial arm binds a second Goniometer (SERIAL-1).
The whole four-circle is an Assembly, not a Family. The sample circles plus the 2theta arm plus det_z plus the reciprocal-space axis compose Assembly(Diffractometer), named-not-built, the 4-ID / 8-ID / i06-1 pattern (DIFF-1, DIFF-2). Composition, not a new role-noun.
The aperture and backlight reuse too. The MAPT binds Aperture on the i03 precedent (APERTURE-1); the backlight is the loose Backlight's fourth sighting (DET-1).

i19 is CORA's first chemical (small-molecule) crystallography beamline, and even so the sample side coins no new Family and changes nothing in the catalog. The genuine i19 novelty is elsewhere: the dual-hutch shared-optics access-control seam, a governance concern over the shared optics, not a device family (ACCESS-1). See the Model page for that seam, the Source walk for the shared optics and the EH1 / EH2 endstation devices in the descriptor, and the Inventory for the full Asset tree.