BMM¶
X-ray absorption spectroscopy at NSLS-II, beamline 6-BM: transmission and fluorescence XAS / EXAFS. This page describes how CORA would model and run BMM; the model is reverse-engineered from public configuration, not yet confirmed by BMM staff.
| Property | Value |
|---|---|
| Asset | BMM (root Asset, tier = Unit, parent_id = None) |
| Facility | NSLS-II (bound via facility_code = "nsls2", FacilityKind = Site) |
| Sector | Sector 6 (PV namespace XF:06BM*) |
| Institution | Brookhaven National Laboratory (context; not modeled as an Asset or Facility) |
| Status | Reverse-engineered from public config (design-phase scaffold) |
| Source | 6-BM bending magnet (SR:C06) |
How CORA would land on BMM
These pages describe how CORA would model, govern, and conduct BMM, the third NSLS-II beamline after FXI and HXN. They are not a survey of the beamline's current software. The hardware facts (devices, EPICS PVs, axes) are read from public NSLS-II open source (the NSLS2/bmm-profile-collection profile collection) and verified against it; vendor part numbers and physical positions are not in it, so they, and every read value, are carried confirm until BMM staff verify them (Open questions). This is a design-phase scaffold: the descriptor and these docs, with scenarios deferred.
The defining shape: an energy scan¶
Every prior CORA deployment measures by scanning position (FXI full-field at a fixed energy, HXN rastering a spot, 2-BM rotating a sample). BMM measures by scanning energy: it sweeps the monochromator across an element's absorption edge and records the incident, transmitted, and reference ion-chamber currents (and a fluorescence spectrum) at each energy point. The absorption, ln(I0/It) versus energy, is the data. This is the spectroscopy axis CORA has not had, and BMM is the first real consumer of the energy_scan Capability the catalog already anticipates (see Techniques).
The beamline¶
Along the beam, in order:
- Source: the bending-magnet source and the optics hutch (
6-BM-A), rendered as the generated source-stage device walk: two mirrors, the double-crystal monochromator, the beam-defining slits, and the attenuating filters. - Sample: the endstation XAFS stages, the sample positioning table, the rotating sample wheel for batch scans, and the reference-foil holder.
- Detector: the XAS detectors read at each energy point, the ion chambers (transmission) and the energy-dispersive detector (fluorescence).
Cutting across all three:
- Controls: the conducting engine that sweeps the energy and reads the detectors per point, and the motion controllers.
The cross-cutting reference view is the Inventory.
Techniques¶
Techniques: what BMM would run (transmission XAS, fluorescence XAS, EXAFS), and the open question of the energy_scan Capability, bound through an NSLS-II Practice.
Governance¶
Governance: who may act at BMM and the trust shape CORA applies; CORA brings its own per-Actor authority.
Model¶
Model: the developer's by-kind index into where each CORA aggregate's BMM content lives.