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Detector

The Eiger, the beamstops, the sample backlight, and the hardware triggers, across both experiment hutches. Design-phase; values are reverse-engineered from dodal, carried confirm.

i19's detection side is the chemical-crystallography counterpart of the MX shape: one Eiger area detector that records the single-crystal diffraction pattern, a beamstop in each experiment hutch, a sample backlight for on-axis viewing, and the FPGA timing boxes that fan out the hardware triggers. The detector itself lives in EH2 with the four-circle; a beamstop and a trigger box sit in each of EH1 and EH2 (which hutch holds what is an Enclosure question, ENC-1). They are modelled in the detection stage of the descriptor.

The detection devices

Device Family Role Control handle Notes
Detector Camera Detector BL19I-EA-EIGER-01: the Eiger area detector, the single-crystal diffraction science detector (EH2) (DET-1)
BeamstopEH1 BeamStop Positioner BL19I-RS-ABSB-01: the EH1 beamstop, with homing (DET-1)
BeamstopEH2 BeamStop Positioner BL19I-OP-ABSB-02: the EH2 beamstop, with homing (DET-1)
Backlight Backlight (loose) Positioner BL19I-EA-IOC-12: sample backlight, in / out illumination for OAV centring (EH2); held under review (DET-1)
TriggerControllerEH1 TimingController Sequencer BL19I-EA-ZEBRA-02: the EH1 Zebra (DET-1)
TriggerControllerEH2 TimingController Sequencer BL19I-EA-ZEBRA-03: the EH2 Zebra (DET-1)
TriggerSequencer TimingController Sequencer BL19I-EA-PANDA-01: the EH2 PandA (DET-1)

The 2theta detector arm and the reciprocal-space pseudo-axis are not detection Assets: they ride the Newport kappa four-circle on the sample side. See Beamline for the source walk and Sample for the four-circle and its arm.

How each maps onto CORA

  • The Eiger reuses Camera. A pixel-array area detector is the Camera Family presenting the Detector Role, the same shape i03's Eiger and the imaging pilots use; here it records the single-crystal diffraction pattern from the four-circle in EH2. The photon-counting specifics (threshold energy) and the beam center are calibration dodal does not carry (DET-1).
  • Both beamstops reuse BeamStop. Each experiment hutch carries one beamstop ahead of the detector path; the homing behaviour is a Positioner affordance on the same mount, not a separate Family. The two are distinct Assets because they are distinct devices in distinct hutches (ENC-1), not a Family split. Their in-position calibration is to confirm (DET-1).
  • The triggers reuse TimingController. Each hutch has a Zebra; EH2 adds a PandA. All three bind the TimingController Family, the same one the 2-BM Timing device and i03's / I22's Zebra and PandA boxes use, confirming that "timing-generation is a first-class device" generalizes across APS and Diamond. The PandA-versus-Zebra distinction is a bound-Model difference on one Family, not two Families (DET-1); which box drives which acquisition is a Method concern, not an Asset one.
  • The backlight presents the Positioner Role, carried loose. The in / out illumination for OAV centring has no existing Family with an illumination affordance, so it binds the loose Backlight family that i03 introduced. This is the 4th sighting (after i03 / i24 / fmx); the family is held under review and is earned to the catalog only on a confirmed rule-of-three, so i19 carries it loose for now (DET-1).

Pin-tip recognition for OAV centring is a Method behaviour over the on-axis viewer and backlight, not a device; the viewing cameras themselves are on the sample side.

Why no new family

The detection side coins nothing. The Eiger is Camera reuse; both beamstops are BeamStop reuse; all three trigger boxes are TimingController reuse with the PandA / Zebra split living in a bound Model rather than in a new Family. The backlight reuses the loose Backlight family rather than minting a fresh one, and stays held pending a rule-of-three (DET-1). No new Family is earned on the detector side and nothing graduates; the catalog is unchanged.

See Families for the bound Families, Inventory for the Asset tree, Model for the modelling decisions, and the Diamond Site for where i19's detection sits among the fleet's diffraction beamlines.