Techniques¶
What 19-BM is designed to do, as intent. Design-phase.
A technique is a portable Catalog Method; a Practice is how a facility adapts it. 19-BM is pre-build, so the techniques below are design intent: the APS Practices that will bind them are carried pending on the APS site page. The function view survives the eventual equipment choices, which is why it can be written before the hardware is procured.
19-BM is a single-mode beamline: filtered white-beam tomography. There is no monochromator and no mirror, so unlike 2-BM there is no beam-mode or energy-change technique. The beam spectrum is set by selecting filters in the F3-30 unit, and the science variety is in the acquisition cadence, not the optics.
| Technique | Catalog Method | What it is for |
|---|---|---|
| Filtered white-beam tomography | tomography |
the standard micron-resolution CT scan |
| Continuous-rotation tomography | continuous_rotation_tomography |
high-throughput acquisition, the autonomous workhorse |
| Streaming tomography | streaming_tomography |
live reconstruction feedback |
| Dark / flat fields | dark_field, flat_field |
the reference frames every reconstruction needs |
| First light | first_light |
commissioning the beam onto the detector |
A few points of intent shape the model:
- Autonomy and throughput are the point. 19-BM is built to run unattended at a high scan cadence with a robotic sample changer feeding it. The technique layer is ordinary tomography; what is distinctive is the autonomous operation around it (see Governance) and the sample-exchange loop (see Sample).
- Spectrum is set by filtering, not optics. Selecting Si / Ge / Cu filters in the F3-30 unit hardens or softens the white-beam spectrum. This replaces the energy-selection techniques 2-BM has, which depend on its monochromator.
- Single beam mode. There is one set of optics and one mode, so there is no beam-mode-change technique to model.
The concrete acquisition recipes (scan sequences, exposure, filter choices) are not written yet; they join as the beamline approaches commissioning. See Open questions for what must be confirmed first.