Demonstration Geometries

Each geometry demonstrated below returns a fully-configured AdHocDiffractometer instance. Geometries are grouped below by their chi-circle mechanism.

Quick start

Pick one of the demo geometries below — for example the six-circle psic instrument — set a wavelength, attach a sample lattice, and print a summary of the diffractometer:

import ad_hoc_diffractometer as ahd

# Use the six-circle psic demo geometry
g = ahd.psic()
g.wavelength = 1.0  # Å

# Define the sample lattice (cubic silicon)
g.sample.lattice = ahd.Lattice(a=5.431)

# Show a summary of the diffractometer
print(g.summary())

To build a four-circle diffractometer step by step — choosing a basis, stacking stages, defining diffraction modes, and running a forward calculation — without starting from a demo geometry, see the Quick Start guide.

Eulerian

The chi circle is a full Eulerian cradle.

• fourch — Eulerian Four-Circle (horizontal)

• fourcv — Eulerian Four-Circle (vertical)

• fivec — Eulerian Five-Circle (Vlieg et al. 1987)

• psic — Eulerian Six-Circle, 4S+2D (You 1999)

• sixc — Eulerian Six-Circle, Surface (Lohmeier & Vlieg 1993)

Kappa

The kappa stage is a replacement for the traditional chi circle.

• kappa4ch — Kappa Four-Circle (horizontal)

• kappa4cv — Kappa Four-Circle (vertical)

• kappa6c — Kappa Six-Circle

Inclination

Geometries designed for surface diffraction or with fully decoupled sample and detector axes.

• s2d2 — S2D2 General-Inclination Four-Circle

• zaxis — Z-Axis Four-Circle (Surface)