TY - JOUR A1 - Fritzsche, Sven A1 - Jaenisch, Gerd-Rüdiger A1 - Pavasaryte, Lina A1 - Funk, Alexander T1 - XCT and DLW: Synergies of Two Techniques at Sub-Micrometer Resolution JF - Applied Science N2 - Direct Laser Writing (DLW) and X-ray computed tomography (XCT) both offer unique possibilities in their respective fields. DLW produces full three-dimensional (3D) polymer structures on the microscale with resolutions below 100 nm. The fabricated structures can be analysed by XCT or X-ray microscopy (XRM), which incorporates additional X-ray lenses, in three dimensions down to a minimal basic spatial resolution of about 500 nm or 50 nm, respectively. In this work, two different DLW structures are analysed via XCT. Internal defects are detected and analysed for the purpose of quality control. Defects and structures with sizes down to 1.5 µm are successfully analysed. A 3D reconstruction and internal, hidden features of the fabricated structures are shown and discussed. In a first-of-its-kind study, we demonstrate the detectability of a single-voxel line inside a fabricated structure that would not be detectable with SEM or light microscopy. Furthermore, the direct fabrication on a PET substrate is shown to overcome the high X-ray absorbance of commonly used glass substrates. Attenuation spectra of SZ2080 and glass substrates are compared to a fabrication route direct on a 170 µm PET foil. The practical aspects of XCT measurements for DLW structures on different substrates will be discussed. KW - Non-destructive testing KW - Two-photon polymerization KW - X-ray microscopy KW - XCT KW - 2PP KW - Direct laser writing PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-560525 DO - https://doi.org/10.3390/app122010488 VL - 12 IS - 20 SP - 1 EP - 15 PB - MDPI CY - Basel AN - OPUS4-56052 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jaenisch, Gerd-Rüdiger A1 - Ewert, Uwe A1 - Waske, Anja A1 - Funk, Alexander T1 - Radiographic Visibility Limit of Pores in Metal Powder for Additive Manufacturing JF - Metals - special isssue - Advanced Characterization and On-Line Process Monitoring of Additively Manufactured Materials and Components N2 - The quality of additively manufactured (AM) parts is determined by the applied process parameters used and the properties of the feedstock powder. The influence of inner gas pores in feedstock particles on the final AM product is a phenomenon which is difficult to investigate since very few non-destructive measurement techniques are accurate enough to resolve the micropores. 3D X-ray computed tomography (XCT) is increasingly applied during the process chain of AM parts as a non-destructive monitoring and quality control tool and it is able to detect most of the pores. However, XCT is time-consuming and limited to small amounts of feedstock powder, typically a few milligrams. The aim of the presented approach is to investigate digital radiography of AM feedstock particles as a simple and fast quality check with high throughput. 2D digital radiographs were simulated in order to predict the visibility of pores inside metallic particles for different pore and particle diameters. An experimental validation was performed. It was demonstrated numerically and experimentally that typical gas pores above a certain size (here: 3 to 4.4 µm for the selected X-ray setup), which could be found in metallic microparticles, were reliably detected by digital radiography. KW - Additive manufacturing KW - Feedstock powder KW - Porosity KW - Digital radiography KW - Numerical simulation PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-517880 DO - https://doi.org/10.3390/met10121634 VL - 10 IS - 12 SP - 1634 PB - MDPI AN - OPUS4-51788 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ewert, U. A1 - Jaenisch, Gerd-Rüdiger A1 - Deresch, A. A1 - Bircher, B. A. A1 - Meli, F. T1 - New concepts for the measurement of focal spot parameters of nano- and microfocus X-ray tubes N2 - Accurate measurement of focal spot sizes of X-ray tubes, betatrons and linear accelerators is still an open problem. Several standards are currently active, which provide different results depending on the focal spot shape. CEN published the standard series EN 12543 (five parts) in 1999, which describes the measurement of focal spot sizes of X-ray tubes for NDT applications. The measurement procedure and its tolerances deviate from the measurement standards for medical X-ray tubes, e.g. EN 60336:2006 / IEC 60336:2005. EN 12543 describes different measurement methods for X-ray tubes with focal spots in several size ranges, defined as macrofocus, minifocus and microfocus. CEN TC 138 WG 1 und ASTM E 07.01 are revising (CEN) or have just revised (ASTM) the standards for focal spot size measurements, basing them on pin hole or edge measurements only. Slit cameras are applied for medical tube evaluation only. Tomographic methods for focal spot size shape reconstruction were proposed and will be discussed, but have not yet been used for standardization. The currently available standards cover the range of spot sizes from 5 µm up to several millimetres. During the last years, more and more nanofocus tubes have been developed for high-resolution applications and microscopy. Manufacturers and users apply different methods for measurement of nanofocus spot sizes and image resolution, which differ by a factor of up to two. These well-known methods and new alternative methods for the measurement of nanofocus spots (size and shape) will be evaluated and improved in the EMPIR project “NanoXSpot” in order to develop a related measurement standard. T2 - International Symposium on Digital Industrial Radiology and Computed Tomography CY - Fürth, Germany DA - 02.07.2019 KW - X-Ray tube KW - Focal spot measurement KW - Standadization PY - 2019 AN - OPUS4-48442 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaenisch, Gerd-Rüdiger A1 - Waske, Anja A1 - Ewert, U. A1 - Bircher, B. A1 - Korpelainen, V. A1 - Costin, M. A1 - Yang, F. A1 - Hörauf, F. A1 - Steffen, J. P. A1 - Dai, G. A1 - Deresch, A. A1 - Graf vom Hagen, C. T1 - EMPIR Project NanoXSpot N2 - The overall objective of project NanoXSpot (Nanometre X-ray Focal Spot Measurement) is to develop traceable measurement methods for determining the focal spot size, shape, and position of nanometre resolution X-ray tubes. The impact of the technical results will be ensured by preparing prenormative documents for submission to CEN TC 138 (Non-destructive testing) WG 1 (Radiographic testing), which directly addresses the research needs of CEN, currently revising standards in the series 12543 for focal spot measurements below 5 µm spot size to harmonise standards and measurement method between ASTM and CEN. T2 - DACH-Tagung CY - Friedrichshafen, Germany DA - 27.05.2019 KW - Standardization KW - X-Ray tube KW - Focal spot measurement PY - 2019 AN - OPUS4-48298 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaenisch, Gerd-Rüdiger A1 - Wieder, Frank A1 - Vogel, Justus A1 - Ewert, Uwe A1 - Bellon, Carsten A1 - Messerschmid, Magdalena ED - Xu, C. T1 - Scatter imaging – Simulation of aperture focusing by deconvolution T2 - Proceedings of 2017 IEEE far east NDT new technology and application forum (FENDT 2017) N2 - X-ray scatter imaging is a well-established NDT technique to inspect complex objects using only a single-sided access. We present a specially designed multi-slit scatter camera consisting of several twisted slits which are parallelly arranged in a metal block. The camera projects one image per slit to the digital detector array, where the images are overlaying each other. The aperture is corrected based on a de-convolution algorithm to focus the overlaying projections into a single representation of the object. To achieve high scatter intensities from an object, it is necessary to optimize the parameters of the scatter system by simulation. T2 - IEEE Far East NDT New Technology & Application Forum CY - Xi'an, China DA - 22.06.2017 KW - Scatter imaging KW - Computer simulation KW - Aperture focusing KW - Deconvolution PY - 2018 SN - 978-1-5386-1615-4 DO - https://doi.org/10.1109/FENDT.2017.8584606 SP - 301 EP - 306 PB - IEEE CY - Piscataway, NJ AN - OPUS4-48395 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -