webdoc Scan API

hugo/content/py/instr/scan/_index.md

++++
+title = "Scan"
+weight = 20
++++
+
+## Scan models
+
+Scans are needed to construct simulations of types
+[reflectometry]({{% ref-py "sim/reflectometry" %}}),
+[off-specular scattering]({{% ref-py "sim/offspec" %}}),
+[depth probe]({{% ref-py "sim/depth-probe" %}}).
+
+There are two types of scan:
+- Alpha scans, for instruments that are mechanically scanning
+  the glancing angle $\alpha\_\text{i}$;
+- Qz scans, for time-of-flight instruments.
+
+### Alpha scans
+
+To specify a scan with `n` equidistant steps in the glancing angle $\alpha\_\text{i}$, use
+```python
+scan = ba.AlphaScan(n, alpha_start, alpha_stop)
+```
+
+Usage is demonstrated by most examples in
+[Examples/specular]({{% ref-src "Examples/specular" %}}).
+
+For other sequences of $\alpha\_\text{i}$ values, use the more generic
+```python
+scan = ba.AlphaScan(axis)
+```
+
+The Axis API may change soon and will be documented then.
+
+After constructing a scan, set the wavelength and optionally a constant offset
+$\delta\alpha\_\text{i}$ using
+```python
+scan.setWavelength(lambda)
+scan.setAlphaOffset(dalpha)
+```
+
+### Qz scans
+
+To specify a scan with `n` equidistant steps in the vertical wavenumber $q_z$, use
+```python
+scan = ba.QzScan(n, qz_start, qz_stop)
+```
+
+Alternatives are
+```python
+scan = ba.QzScan(q_vector)
+```
+and
+```python
+scan = ba.QzScan(axis)
+```
+
+{{% children  %}}