POWTEX is a TOF neutron powder diffractometer at MLZ. Funded by the Federal Ministry of Research, Technology and Space (BMFTR, 05K22PA2, 05K23PAA), it is built by RWTH Aachen University and Forschungszentrum Jülich. Dedicated texture sample environments are contributed from the Geo Science Centre, Göttingen University. POWTEX aims for short measurement times and in situ chemical experiments, e.g., phase-transitions as a function of *T*, *p*, and *B*₀. For texture-analysis, in situ deformation, annealing, simultaneous stress, etc., the large angular coverage drastically reduces the need for sample tilting/rotation. Several new concepts have been developed, which are now also being used in other instruments. The necessary components have long since been built, and significant progress was made on their installation in 2025/2026. The two double-elliptic neutron-guides featuring octagonal cross sections with graded super-mirror coating focus on the sample, resulting in Gaussian intensity and divergence distributions. Their common focal point at the pulse-chopper serves as “eye of a needle” in time and space, optimizing time-resolution and reducing the source background. The innovative, solid-¹⁰B jalousie volume-detector was tailormade for POWTEX and achieves high efficiency for a remarkably large coverage of nine steradians with almost no blind spots. As regards theoretical concepts, multidimensional data-reduction algorithms handling angular- and wavelength-dispersive datasets have been developed and implemented, e.g. in Mantid, resulting intensity as function of the orthogonal coordinate system *d*, *d*_⊥ as alternative to the complementary λ vs. 2θ coordinates. This very procedure, in addition to analytical instrument parametrizations based on fundamental design values, has allowed for multidimensional Rietveld-analysis using a modified version of GSAS-II for various TOF diffractometers (POWGEN@ORNL, POWTEX@POWGEN@ORNL, SNAP@ORNL) and also various samples (powdered diamond, BaZn(NCN)₂, PbNCN, Fe(dca)₂(py)₂), hence demonstrating the broad applicability of the method. The CIF Powder Dictionary was extended by the definition of `d_spacing_perpendicular` as data name for *d*_⊥ as well. The POWTEX design and status of implementation and the data-workflow as use case in DAPHNE4NFDI (DFG 460248799) are presented.

MLZ User Meeting 2026

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