Detector

The six-circle spectrometer arm, the diced crystal energy analyzer, its thermal stabilization, and the counting detectors. First cut; PVs read from the profile collection, carried confirm.

IXS detection is momentum-resolved and energy-analyzed, not imaging: a six-circle scattering arm carries a fixed diced crystal analyzer that Bragg-reflects the scattered beam to select a single final energy, focusing the energy-selected photons onto point detectors that integrate the current. The arm sets the momentum transfer Q, the analyzer fixes the final energy, and the incident energy is scanned upstream (the DCM and the high-resolution monochromator) to build I(Q, energy-loss). They are modelled in the detection stage of the descriptor.

The spectrometer arm reuses the catalog Goniometer Family (the 8-ID / 4-ID six-circle diffractometer anatomy, driven by the reciprocal-space PseudoAxis); the crystal analyzer binds a loose EnergyAnalyzer Family (no catalog or loose Family fits a driven diced-crystal Bragg analyzer, see Model); its thermal stabilization reuses the catalog TemperatureController; and the counting detectors reuse FluxMonitor.

Detection chain

Device	Family	Design spec / note
Spectrometer	Goniometer	six-circle scattering arm (2Th / Th / ChiA / PhiA); the scattering angle two_theta sets \|Q\|, driven by the reciprocal-space pseudo-axis (ANALYZER-1 for the Assembly question)
ReciprocalSpace	PseudoAxis	six-circle H / K / L reciprocal-space axis over the arm via the SixCircle kinematics; the derived angles present a Sensor read-back facet (ENERGY-1)
EnergyAnalyzer	EnergyAnalyzer (loose)	diced crystal Bragg energy analyzer, six diced crystals d1-d6, each with theta / phi and PID temperature; selects a fixed final energy (ANALYZER-1, XTAL-1)
AnalyzerSlit	Slit	analyzer-chamber beam-defining slit (top / bottom / inboard / outboard) (OPT-2)
AnalyzerThermalControl	TemperatureController	per-crystal PID thermal stabilization for energy stability, six PID channels (TEMP-1, XTAL-1)
AnalyzerElectrometers	FluxMonitor	quad electrometers reading the energy-analyzed scattered signal as a scalar current, the science point detector (DET-1)
IncidentScaler	FluxMonitor	counting scaler; the I0 channel is the incident-flux monitor for normalization (DET-1)

The chain reads outward from the sample. The six-circle arm points the analyzer at the scattered beam and sets the magnitude of the momentum transfer through its scattering angle, with the reciprocal-space pseudo-axis driving the four angles together so a run can step in H / K / L. The analyzer then selects one final energy and focuses the energy-selected photons onto photodiodes, which the quad electrometers read as a current; the scaler I0 channel records the incident flux for normalization. Detection is point and current-integrating, so there is no area detector and no per-pixel readout: the energy axis is built by scanning the incident energy, not by dispersing the beam across a sensor. The channel map, and whether the analyzer-focus photodiode is a separate Asset or just an electrometer channel, is DET-1 (default: a channel).

The crystal energy analyzer

The energy analyzer is the signature IXS instrument and the one device class no existing Family covers. It is a diced multi-crystal Bragg analyzer: six diced crystals, each carrying its own theta / phi orientation and PID temperature stabilization, that reflect the scattered beam to a fixed final energy. No catalog or loose Family fits this anatomy. It is not the catalog EnergyDispersiveSpectrometer (a per-event point Sensor that reads energy, where here the analyzer positions crystals and the reading happens downstream at the electrometers), nor the catalog Monochromator (an upstream incident-beam optic), nor SIX's loose SpectrometerArm (a soft X-ray energy-dispersive arm, where IXS uses a driven scanning crystal analyzer rather than a dispersive one).

So it is coined as one loose EnergyAnalyzer Family, held at n=1 and graduating nothing: a second independent hard crystal-analyzer beamline must earn the abstraction before any catalog change. The name was cleared by the naming-r3 gate as the <Quantity>Analyzer sibling of 4-ID's loose PolarizationAnalyzer (the qualifier names the analyzed quantity), avoiding the CrystalAnalyzer / AnalyzerCrystal read-aloud homograph. Whether EnergyAnalyzer and PolarizationAnalyzer later merge into one Analyzer Family differentiated by a setting is the open ANALYZER-1, a gate decision at the second sighting.

The six diced crystals are carried as settings on the one EnergyAnalyzer Asset for this first cut, even though each is identity-bearing (its own theta / phi and its own temperature loop). Promoting each crystal to a child Asset via parent_id is exactly the nested-component-identity convention, which is itself at a rule-of-three gate, so IXS flags XTAL-1 as a candidate trigger rather than asserting it. The six crystal-temperature PID loops are carried as one TemperatureController Asset for the same reason (TEMP-1). Whether the arm plus the analyzer compose an Assembly(Diffractometer)-style Fixture is ANALYZER-1, named as the follow-on the way 8-ID and 4-ID deferred their diffractometer Assemblies.

Families

Reused from the catalog: Goniometer (the six-circle arm), PseudoAxis (the reciprocal-space axis), Slit (the analyzer slit), TemperatureController (the per-crystal thermal stabilization), and FluxMonitor (the quad electrometers and the I0 scaler). New at n=1: the EnergyAnalyzer Family for the diced crystal analyzer, held loose until a second hard crystal-analyzer / IXS beamline earns it (ANALYZER-1). The diced-crystal child-Asset identity is XTAL-1 and the electrometer / scaler channel map is DET-1. See Inventory for the Asset tree.