TY - JOUR A1 - Böttcher, Katrin A1 - Schmitt Rahner, M. A1 - Stolzenberg, U. A1 - Kraft, Sebastian A1 - Bonse, Jörn A1 - Feist, C. A1 - Albrecht, D. A1 - Pullner, B. A1 - Krüger, Jörg T1 - Worst-case X-ray photon energies in ultrashort pulse laser processing N2 - Ultrashort pulse laser processing can result in the secondary generation of unwanted X-rays if a critical laser irradiance of about 10^13 W/cm^2 is exceeded. Spectral X-ray emissions were investigated during the processing of tungsten and steel using three complementary spectrometers (based on CdTe and silicon drift detectors) simultaneously for the identification of a worst-case spectral scenario. Therefore, maximum X-ray photon energies were determined, and corresponding dose equivalent rates were calculated. An ultrashort pulse laser workstation with a pulse duration of 274 fs, a center wavelength of 1030 nm, pulse repetition rates between 50 kHz and 200 kHz, and a Gaussian laser beam focused to a spot diameter of 33 µm was employed in a single pulse and burst laser operation mode. Different combinations of laser pulse energy and repetition rate were utilized, keeping the average laser power constant close to the maximum power of 20 W. Peak irradiances ranging from 7.3 × 10^13 W/cm^2 up to 3.0 × 10^14 W/cm^2 were used. The X-ray dose equivalent rate increases for lower repetition rates and higher pulse energy if a constant average power is used. Laser processing with burst mode significantly increases the dose rates and the X-ray photon energies. A maximum X-ray photon energy of about 40 keV was observed for burst mode processing of tungsten with a repetition rate of 50 kHz and a peak irradiance of 3 × 10^14 W/cm^2. KW - Ultrashort pulsed laser KW - X-ray emission KW - X-ray spectrum KW - X-ray energies KW - Radiation protection PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-566176 DO - https://doi.org/10.3390/ma15248996 VL - 15 IS - 24 SP - 1 EP - 17 PB - MDPI AN - OPUS4-56617 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kraft, S. A1 - Böttcher, Katrin A1 - Bonse, Jörn A1 - Schille, J. A1 - Löschner, U. A1 - Krüger, Jörg T1 - Unwanted X-ray emission in ultrashort pulse laser processing: From metallic to biological materials N2 - X-rays can be generated as an unwanted side effect during ultrashort pulse laser material processing of technical work pieces and even biological samples with laser intensities above 10^13 W/cm^2. First studies demonstrate the need to address this effect in industrial as well as in medical applications. This secondary hazard should be considered in work safety and risk assessment. T2 - Lasers in Manufacturing 2023 (LiM 2023) CY - Munich, Germany DA - 26.06.2023 KW - Ultrashort pulse laser processing KW - Laser-induced X-ray emission KW - Secondary hazard PY - 2023 SP - LiM 2023 - 1 EP - LiM 2023 - 6 PB - Wissenschaftliche Gesellschaft Lasertechnik und Photonik e.V. (WLT) AN - OPUS4-58358 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jahnke, Annika A1 - Beck, Aaron J. A1 - Becker, Richard L. A1 - Bedulina, Daria A1 - Braun, Ulrike A1 - Gerdts, Gunnar A1 - Hildebrandt, Lars A1 - Joerss, Hanna A1 - Klein, Ole A1 - Korduan, Janine A1 - Laforsch, Christian A1 - Lannig, Gisela A1 - Leslie, Heather A. A1 - Lips, Stefan A1 - Menger, Frank A1 - Nabi, Deedar A1 - Oberbeckmann, Sonja A1 - Primpke, Sebastian A1 - Pröfrock, Daniel A1 - Ramsperger, Anja F.R.M. A1 - Römerscheid, Mara A1 - Schmitt-Jansen, Mechthild A1 - Scholz-Böttcher, Barbara M. A1 - Tröppner, Oliver A1 - Wendt-Potthoff, Katrin A1 - Kühnel, Dana T1 - Perspective article: Multisectoral considerations to enable a circular economy for plastics N2 - Plastics are widely used but improper disposal and release lead to increasing global pollution, threatening environmental and human health. To address this issue, we suggest intersectoral collaboration to achieve zero plastic pollution. The outcomes of the project P-LEACH demonstrated the enormous complexity and range of potential toxic effects of plastic-associated chemicals and micro-/nanoplastics released into water from UV-weathered plastics. We initiated an intersectoral dialogue amongst scientists, manufacturers, regulators and representatives of civil society about how to alleviate the negative impacts of plastic pollution. Circular economy offers a framework for selecting non-toxic chemicals, extending product (re)use, and waste reduction, which act to alleviate pollution when applied to plastics. We suggest three measures to advance a circular economy of plastics: 1.) Increase simplicity of chemicals in virgin plastics combined with transparent information on the contents; 2.) Consider recyclability already in plastic material and product design; 3.) Foster communication through intersectoral dialogue. Major cornerstones are the provision of standardized, easy-to-use tools to characterize plastics and plastic leachates chemically and (eco)toxicologically, the enhancement of citizen awareness enabling them to make informed choices, the creation of economic incentives for manufacturers, and sector-specific regulations to provide products that safeguard environmental and human health. KW - Plastics KW - Circular economy KW - Cross-sectoral dialogue KW - Recyclability KW - Plastic-associated chemicals PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-638280 DO - https://doi.org/10.1016/j.jhazmat.2025.139326 SN - 0304-3894 VL - 496 SP - 1 EP - 9 PB - Elsevier B.V. AN - OPUS4-63828 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Böttcher, Katrin A1 - Kraft, Sebastian A1 - Weise, Matthias A1 - Bonse, Jörn A1 - Krüger, Jörg T1 - Publisher correction: X-ray emission during ultrafast laser grooving N2 - This is a corrigendum to the original article "X-ray emission during ultrafast laser grooving" that was published in the journal "Applied Physics A", vol. 131 (2025), article 651 (doi 10.1007/s00339-025-08728-z). PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-648868 DO - https://doi.org/10.1007/s00339-025-08882-4 SN - 0947-8396 VL - 131 IS - 11 SP - 1 PB - Springer CY - Berlin AN - OPUS4-64886 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Böttcher, Katrin A1 - Kraft, Sebastian A1 - Weise, Matthias A1 - Bonse, Jörn A1 - Krüger, Jörg T1 - X-ray emission during ultrafast laser grooving N2 - Ultrashort pulse lasers offer the possibility to process materials with minimal heat input and high precision. However, the X-ray emission at high laser peak intensities represents an undesirable side effect. A laser system (1030 nm wavelength, 40 W maximum average laser power, 925 fs pulse duration, 100 μJ maximum pulse energy, 400 kHz pulse repetition frequency) was used to analyze the X-ray skin dose rates for applied peak intensities between 9.2 × 10^12 W/cm^2 and 1.3 × 10^14 W/cm^2 for mild steel, stainless steel and tungsten during groove processing. The lowest laser peak intensity at which X-ray emission could be measured was 9.2 × 10^12 W/cm^2 for processing of stainless steel. The X-ray emission showed a characteristic evolution in dependence on the number of overscans at the same line positions. For low peak intensities, a measurable X-ray emission only begins after a few passes. The number of scans to reach the maximum dose rate increases with lower laser peak intensity. Analysis of the evolving surface topography by white light interference microscopy in connection with ray-tracing simulations led to the interpretation that the increase in X-ray emission is due to the local intensity redistribution by multiple reflection within the laser-generated grooves which is promoted by a particular choice of the linear laser polarization. KW - Ultrashort pulsed laser KW - Laser-induced X-rays KW - X-ray hazard KW - X-ray emission PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639483 DO - https://doi.org/10.1007/s00339-025-08728-z SN - 1432-0630 VL - 131 IS - 8 SP - 1 EP - 12 PB - Springer CY - Berlin AN - OPUS4-63948 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -