Research Data Repository of Saxon Universities
OPARA is the Open Access Repository and Archive for Research Data of Saxon Universities.
Researchers of Saxon Universities can either publish their research data on OPARA, or archive it here to comply with requirements of funding acencies and good scientic practice, without public access.
You can find the documentation of this service at the ZIH Data Compendium websites. If you need suppourt using OPARA please contact the Servicedesk of TU Dresden.
Please note: The OPARA service was recently upgraded to a new technical platform (this site). Previously stored data will not be available here immediately. It can be found at the still active old version of OPARA. These stock data will be migrated in near future and then the old version of OPARA will finally be shut down. Existing DOIs for data publications remain valid.
Communities in OPARA
Select a community to browse its collections.
Recent Submissions
Charge Particle Optics Simulation Utilizing Hamiltonian Mechanics Perturbation Expansion and Boundary Elements Field Computation
(Technische Universität Dresden, 2026-05-26) Lubk, Axel; Houdellier, Florent; Müller, Heiko; Uhlemann, Stephan
Background incl. aims
Advanced charge particle optics (CPO) requires fast and accurate computational tools for calculating (relativistic) particle trajectories including aberrations that, ideally, handle both arbitrary electrics and magnetic field sources, handle arbitrarily bend optical axis, allow incorporation of symmetries (e.g., rotational or mirror), incorporate optimization of design parameters such as pole piece diameter or pole distances. Ideally such tools should also be available under open source licenses in order to facilitate widespread use as well as distributed and sustainable development. Despite the enormous level of development and usefulness of commercial (e.g. Simion, EOD, Comsol) and open source packages, they often lack a subset of the above functionalities, somewhat hampering a wide spread development and use of advanced CPO for, e.g., Transmission Electron Microscopy, Secondary Ion Mass Spectroscopy, Photo Electron Spectroscopy, in academia, industry, and also teaching. The CPO software development described below intends to address that need.
Methods
Here we report on the development of an open source computational CPO framework incorporating the following principles to allow for an accurate, fast and flexible trajectory calculation: (A) We use boundary element method (BEM) computation of electric and magnetic fields, yielding smooth and accurate potentials, fields and higher-order derivatives at optical axis at arbitrary sampling, while reducing the meshing effort to surfaces (e.g., electrodes and pole pieces) of the CPO device. Herein, single layer representations of both electric and magnetic scalar potential are most efficient, while Green’s representation with Calderon preconditioning allows stable single step solution of magnetic field distributions in the presence of high µr materials. (B) We employ semianalytical hierarchical solution of perturbation series of Hamiltonian equations of motion around an optical axis[1] in order to provide computationally effective, fast and accurate built-up of aberrations along particle trajectories. While not implemented yet the Hamiltonian perturbation expansion also facilitates straight forward extension to curved axis and the eikonal representation of aberrations. (C) We integrate the fast field and particle trajectory computation with non-linear optimization routines facilitating automatic optimization of design parameters (e.g., multipole sizes, pole piece gap) with respect to certain target functionalities. This tool chain is written in Python and makes use of advanced open source libraries (namely OpenCascade for CAD, gmsh for meshing, BEMPP for BEM field computation, sympy for semianalytic Hamiltonian mechanics perturbation expansion including automatic code generation, scipy for solving equations of motion, nlopt for geometry optimization) in a modular way, which are partly adapted to the specifics of CPO. Notably, BEMPP was extended by parallel just-in-time compiled numba and opencl kernels for field derivative computations on optical axis as required for computation of paraxial trajectories and aberrations.
Results
We demonstrate and discuss the above tool chain with the help several electrostatic and magnetostatic CPO / building blocks of CPO, notably electrostatic Einzellens, electrostatic quadrupole – round aperture assembly (see Fig. 1) and magnetostatic quadrupole, touching implementation (e.g., CAD import, defining boundary conditions, vector potential gauge), numerical (e.g., mesh size, precision of paraxial solution) and CPO (e.g., chromatic and geometric aberrations) aspects.
Conclusion
A modular combination of adapted BEM field computations and semianalytical perturbation series expansion of Hamiltonian equations of motion admits a computationally efficient modeling of CPO utilizing a combination of powerful and freely available open source software packages. Further development aims at incorporation of curved optical axis and general enhancement of functionality and user friendliness in order to support development of advanced CPO across the community.
Reference:
[1] Kern, F., Krehl, J., Thampi, A., Lubk, A. “A Hamiltonian mechanics framework for charge particle optics in straight and curved systems”, Optik, 2021, 242, 167242
[2] Tamura, K., Okayama, S., Shimizu, R. “Third-order spherical aberration correction using multistage self-aligned quadrupole correction-lens systems”, Journal of Electron Microscopy, 2010, 59, 197
[3] We acknowledge financial support by the European Union's Horizon Europe framework program for research and innovation under grant agreement n. 101094299 (IMPRESS project).
Original research data of "Tunable-Threshold UV Dosimetry with Programmable Luminescent Tags via Oxygen-Mediated Room-Temperature Phosphorescence"
(Technische Universität Dresden, 2026-05-19) Achenbach, Tim; Will, Paul-Anton; Schellhammer, Sebastian; Reineke, Sebastian
Original research data to the following paper: Accurate monitoring of UV radiation is critical across numerous disciplines, yet bridging the gap between complex electronic devices and ambiguous, gradual colorimetric indicators remains challenging. Addressing this challenge, a novel approach for a customizable, purely organic UV threshold dosimeter based on oxygen-mediated room-temperature phosphorescence (RTP) is presented. The active layer comprises a purely organic emitter (BP-2TA) dispersed in a poly(methyl methacrylate) (PMMA) host, protected by a polyvinyl alcohol layer. Upon UV irradiation, photochemical oxygen consumption yields a high-contrast, sharp turn-on of the emitter’s phosphorescent emission once a specific cumulative UV dose is reached. This activation depends strictly on the cumulative dose rather than irradiation intensity and is systematically tunable by adjusting the emitter concentration. A comprehensive physical model is introduced that describes the wavelength and thickness dependencies, revealing a thin-film regime where the activation dose becomes independent of the active layer thickness. Supported by shelf-life stability tests, these findings, alongside the proposed operational modes, establish the RTP-based sensors as robust UV dosimeters that could be easily integrated into production processes.
Farnesischer Stier - Kithara und Baumstammende, Universität Leipzig, Antikenmuseum, G 661 - TF 2, high-poly
(Universität Leipzig, 2026-05-18) Michalski, Paula; Apelt, Joana
Dieser Datensatz enthält das High-Poly-Modell der Kithara und eines Baumstammendes aus der Gipsabformung der Skulpturengruppe des Farnesischen Stiers, die sich im Antikenmuseum der Universität Leipzig (Inventarnummer G 661, TF 2) befindet. Das 3D-Modell basiert auf den hochaufgelösten Rohdaten und wurde durch Polygonreduktion optimiert. Dabei blieb die geometrische und visuelle Qualität erhalten, während die Dateigröße deutlich reduziert wurde.
Farnesischer Stier - Linker Vorderlauf des Stiers, Universität Leipzig, Antikenmuseum, G 661 - TF 4, high-poly
(Universität Leipzig, 2026-05-18) Michalski, Paula; Apelt, Joana
Dieser Datensatz enthält das High-Poly-Modell des linken Vorderlaufs des Stiers aus der Gipsabformung der Skulpturengruppe des Farnesischen Stiers, die sich im Antikenmuseum der Universität Leipzig (Inventarnummer G 661, TF 4) befindet. Das 3D-Modell basiert auf den hochaufgelösten Rohdaten und wurde durch Polygonreduktion optimiert. Dabei blieb die geometrische und visuelle Qualität erhalten, während die Dateigröße deutlich reduziert wurde.
Supplemental SEM-EDS (MLA) and CT data for the publication "CNN-based 3D characterization and liberation analysis of lithium-bearing slag particles using correlative CT and SEM imaging"
(Technische Universität Bergakademie Freiberg, 2026-05-13) Ditscherlein, Ralf
This dataset provides the underlying X-ray CT data and processed image stacks used for particle-scale characterization and evaluation of the proposed workflow. The study addresses the challenge of accurately characterizing lithium-bearing slag particles to improve recovery of critical raw materials. A correlative workflow combining 3D CT imaging with 2D SEM-based mineral maps is used to train convolutional neural networks for phase-wise and particle-wise segmentation. This enables scalable 3D characterization with minimal manual labeling effort. The models are applied to particle size fractions of 63–100 µm and 100–250 µm. Results show that conventional 2D approaches systematically overestimate mineral liberation, while the presented 3D approach reduces stereological bias and provides more reliable input for process optimization.