The Eulerian Cradle of D9

The Eulerian Cradle is the central part of a 4-circle diffractometer such as D9. Two circles, denoted φ and χ, are used to adjust the crystal orientation relative to the diffractometer axes. A third circle, ω, sets the orientation of the crystal lattice planes to the diffraction position. Finally the fourth circle 2θ, rotates the detector to the diffracted beam. The closed Eulerian Cradle of D9 is stout enough to accommodate sample environment devices such as a cryocooler, a closed shell furnace, etc.