Dr. Timm Weitkamp Profile

Dr. Timm Weitkamp

at Synchrotron SOLEIL

SPIE Involvement:

Author

Websites:

Company Website | Personal Website

Publications (41)

Proceedings Article | 9 May 2024 Poster + Paper

Hard x-ray nanotomography of dental composites for wide color matching

Dimitrios Tripkis, Mattia Humbel, Hans Deyhle, Georg Schulz, Mario Scheel, Timm Weitkamp, Bert Müller

Proceedings Volume 12944, 129440G (2024) https://doi.org/10.1117/12.3012813

KEYWORDS: Optical transmission, Dental materials, Matrices, Particles, X-rays, Composites, X-ray microscopy, Transmittance, Synchrotrons, Dentistry

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Caries affects billions of individuals worldwide, thus pointing out the importance of advancements in restorative dentistry. Dental resin composites yield restorations with satisfying mechanical properties, therefore the focus of development has shifted to accelerated treatments and esthetic aspects. Challenges in matching tooth color arise due to limited options, application changes, and color variations over time. Single-shade composites with the 'chameleon effect' adapt their color to the surrounding enamel by closely matching the tooth's optical spectrum, enhancing color blending. Structural color, based on light interference, contributes to this effect. The study investigates the submicron filler particles' impact on optical properties and the chameleon effect. Four single-shade dental resin composite materials were investigated. Needle-like samples about 100 μm in diameter were prepared and imaged in a scanning electron microscope. Light transmission through the materials for wavelengths between 200 and 900 nm was measured using a spectrophotometer. Three-dimensional nanotomography data were obtained through transmission X-ray microscopy at the ANATOMIX beamline, Synchrotron SOLEIL, France in both absorption and Zernike phase contrast mode with 23 nm voxel size. The real space information was complemented with small-angle X-ray scattering. These experiments revealed substantial differences in the microscopic structure of the materials. In the case of Omnichroma, the filler consists of almost identical spheres with a diameter of 260 nm while Filtek Universal exhibits polydisperse, irregularly shaped fillers. Additionally, Venus Pearl One’s fillers have a polyhedral shape and a wide size distribution. Finally, the setups used did not reveal any clearly identified microstructure of the Chroma Fill composite. Although all investigated materials are known to exhibit the chameleon effect, their differences in micro- and nanostructure call into question previous hypotheses on the chameleon effect’s origin from structural color. While we have now a reasonable understanding of filler morphology, size distribution and spatial arrangement, more information is needed on the exact chemical composition of filler and matrix and their interaction with electromagnetic waves, including possible nonlinear effects.

Proceedings Article | 17 November 2022 Presentation + Paper

Three-dimensional imaging of porcine joints down to the subcellular level

Georg Schulz, Andrea Barbero, Francine Wolf, Griffin Rodgers, Christine Tanner, Timm Weitkamp, Marcus Mumme, Marta Morawska, Daniel Beer, Bert Müller

Proceedings Volume 12242, 1224215 (2022) https://doi.org/10.1117/12.2635223

KEYWORDS: Cartilage, Visualization, Tissues, X-rays, Bioalcohols, Bone, Laser ablation, Tomography, Synchrotrons, Spatial resolution

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Proceedings Article | 10 November 2022 Paper

Tomographic imaging of unique objects: annual layers in tooth cementum of Anna Catharina Bischoff born 1719

Jeannette Von Jackowski, Bert Müller, Georg Schulz, Gerhard Hotz, Timm Weitkamp, Ursula Wittwer-Backofen, Christine Tanner

Proceedings Volume 12242, 122421O (2022) https://doi.org/10.1117/12.2635312

KEYWORDS: Teeth, Visualization, Optical microscopy, Radiography, Cements, Tomography, Computed tomography, Synchrotrons, Spatial resolution, Photomicroscopy

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Proceedings Article | 14 October 2022 Presentation + Paper

Nano-tomography of dental composites with wide color matching

Mattia Humbel, Mario Scheel, Christine Tanner, Griffin Rodgers, Georg Schulz, Corinne Carlucci, Jeannette von Jackowski, Guido Sigron, Andrés Izquierdo, Timm Weitkamp, Bert Müller

Proceedings Volume 12242, 122420Q (2022) https://doi.org/10.1117/12.2635928

KEYWORDS: Refractive index, Optical spheres, Teeth, Polymers, Particles, Composites, X-ray microscopy, Tomography, Monte Carlo methods, Transmittance, Disordered photonic crystals, Photorefractive polymers

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Proceedings Article | 14 October 2022 Paper

Mosaic microtomography of a full mouse brain with sub-micron pixel size

Griffin Rodgers, Christine Tanner, Georg Schulz, Timm Weitkamp, Mario Scheel, Marta Girona Alarcón, Vartan Kurtcuoglu, Bert Müller

Proceedings Volume 12242, 122421L (2022) https://doi.org/10.1117/12.2633556

KEYWORDS: MATLAB, Visualization, Sensors, Image segmentation, Tomography, Synchrotrons, Reconstruction algorithms, Neuroimaging, Brain mapping, Brain

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Proceedings Article | 14 October 2022 Presentation + Paper

Hierarchical imaging of African bovid tooth cementum using x-ray microtomography

Adriana Velasco, Christine Tanner, Georg Schulz, Griffin Rodgers, Jeannette von Jackowski, Mattia Humbel, Timm Weitkamp, Henry Bunn, Bert Müller

Proceedings Volume 12242, 122420R (2022) https://doi.org/10.1117/12.2633043

KEYWORDS: Statistical analysis, Teeth, Visualization, X-rays, Cements, Tomography, Synchrotrons, X-ray imaging, Synchrotron x-ray imaging, Anthropology

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Proceedings Article | 20 April 2022 Presentation + Paper

Three-dimensional imaging and analysis of annual layers in tree trunk and tooth cementum

Bert Müller, Muriel Stiefel, Griffin Rodgers, Mattia Humbel, Melissa Osterwalder, Jeannette von Jackowski, Gerhard Hotz, Adriana Velasco Guadarrama, Henry Bunn, Mario Scheel, Timm Weitkamp, Georg Schulz, Christine Tanner

Proceedings Volume 12041, 120410C (2022) https://doi.org/10.1117/12.2615148

KEYWORDS: Teeth, Visualization, Image segmentation, X-rays, Tomography, Spatial resolution, Hard x-rays, 3D image processing

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SPIE Journal Paper | 31 March 2022 Open Access

Comparative hard x-ray tomography for virtual histology of zebrafish larva, human tooth cementum, and porcine nerve

Alexandra Migga, Georg Schulz, Griffin Rodgers, Melissa Osterwalder, Christine Tanner, Holger Blank, Iwan Jerjen, Phil Salmon, William Twengström, Mario Scheel, Timm Weitkamp, Christian Schlepütz, Jan S. Bolten, Jörg Huwyler, Gerhard Hotz, Srinivas Madduri, Bert Müller

JMI, Vol. 9, Issue 03, 031507, (March 2022) https://doi.org/10.1117/12.10.1117/1.JMI.9.3.031507

KEYWORDS: Tomography, Teeth, Nerve, Spatial resolution, Hard x-rays, Cements, Synchrotrons, Imaging systems, Tissues, Data acquisition

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Purpose: Synchrotron radiation-based tomography yields microanatomical features in human and animal tissues without physical slicing. Recent advances in instrumentation have made laboratory-based phase tomography feasible. We compared the performance of three cutting-edge laboratory systems benchmarked by synchrotron radiation-based tomography for three specimens. As an additional criterion, the user-friendliness of the three microtomography systems was considered. Approach: The three tomography systems—SkyScan 2214 (Bruker-microCT, Kontich, Belgium), Exciscope prototype (Stockholm, Sweden), and Xradia 620 Versa (Zeiss, Oberkochen, Germany)—were given 36 h to measure three medically relevant specimens, namely, zebrafish larva, archaeological human tooth, and porcine nerve. The obtained datasets were registered to the benchmark synchrotron radiation-based tomography from the same specimens and selected ones to the SkyScan 1275 and phoenix nanotom m® laboratory systems to characterize development over the last decade. Results: Next-generation laboratory-based microtomography almost reached the quality achieved by synchrotron-radiation facilities with respect to spatial and density resolution, as indicated by the visualization of the medically relevant microanatomical features. The SkyScan 2214 system and the Exciscope prototype demonstrated the complementarity of phase information by imaging the eyes of the zebrafish larva. The 3-μm thin annual layers in the tooth cementum were identified using Xradia 620 Versa. Conclusions: SkyScan 2214 was the simplest system and was well-suited to visualizing the wealth of anatomical features in the zebrafish larva. Data from the Exciscope prototype with the high photon flux from the liquid metal source showed the spiral nature of the myelin sheaths in the porcine nerve. Xradia 620 Versa, with detector optics as typically installed for synchrotron tomography beamlines, enabled the three-dimensional visualization of the zebrafish larva with comparable quality to the synchrotron data and the annual layers in the tooth cementum.

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Proceedings Article | 7 October 2021 Presentation + Paper

Extended-field synchrotron microtomography for non-destructive analysis of incremental lines in archeological human teeth cementum

Christine Tanner, Griffin Rodgers, Georg Schulz, Melissa Osterwalder, Gabriela Mani-Caplazi, Gerhard Hotz, Mario Scheel, Timm Weitkamp, Bert Müller

Proceedings Volume 11840, 1184019 (2021) https://doi.org/10.1117/12.2595180

KEYWORDS: Teeth, Sensors, Image segmentation, Radiography, Nondestructive evaluation, Linear filtering, Cements, Tomography, Image enhancement, Synchrotrons

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Proceedings Article | 7 October 2021 Presentation + Paper

Laboratory-based phase and absorption tomography for micro-imaging of annual layers in human tooth cementum, paraffin-embedded nerve and zebrafish embryo

Alexandra Migga, Georg Schulz, Griffin Rodgers, Melissa Osterwalder, Christine Tanner, Holger Blank, Iwan Jerjen, Phil Salmon, William Twengström, Mario Scheel, Timm Weitkamp, Christian Schlepütz, Jan Bolten, Jörg Huwyler, Gerhard Hotz, Srinivas Madduri, Bert Müller

Proceedings Volume 11840, 118400T (2021) https://doi.org/10.1117/12.2597926

KEYWORDS: Teeth, Nerve, Tissues, Tomography, Data acquisition, Synchrotrons, Spatial resolution, Synchrotron radiation

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Proceedings Article | 9 September 2021 Presentation + Paper

Impact of fixation and paraffin embedding on mouse brain morphology: a synchrotron radiation-based tomography study

Griffin Rodgers, Christine Tanner, Georg Schulz, Alexandra Migga, Timm Weitkamp, Willy Kuo, Mario Scheel, Melissa Osterwalder, Vartan Kurtcuoglu, Bert Müller

Proceedings Volume 11840, 118400P (2021) https://doi.org/10.1117/12.2595144

KEYWORDS: Visualization, Tissues, X-rays, Bioalcohols, Synchrotrons, Neuroimaging, Cerebellum, Brain

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Proceedings Article | 31 March 2021 Presentation + Paper

Non-rigid registration to determine strain fields during mouse brain fixation and embedding

Griffin Rodgers, Georg Schulz, Willy Kuo, Mario Scheel, Vartan Kurtcuoglu, Timm Weitkamp, Bert Müller, Christine Tanner

Proceedings Volume 11586, 115860I (2021) https://doi.org/10.1117/12.2583632

KEYWORDS: Tissues, X-ray microscopy, Tomography, Synchrotrons, Biological research, Synchrotron radiation, Neuroimaging, X-ray imaging, States of matter, Brain

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Proceedings Article | 10 September 2019 Presentation + Paper

Correction of phase wrapping artifacts in grating-based hard x-ray tomography

Griffin Rodgers, Georg Schulz, Hans Deyhle, Shashidhara Marathe, Christos Bikis, Bert Müller, Timm Weitkamp

Proceedings Volume 11113, 1111308 (2019) https://doi.org/10.1117/12.2530709

KEYWORDS: Data modeling, X-rays, Tomography, Reconstruction algorithms, Phase measurement, Phase shifts

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Proceedings Article | 11 September 2014 Paper

Grating interferometry-based phase microtomography of atherosclerotic human arteries

Marzia Buscema, Margaret Holme, Hans Deyhle, Georg Schulz, Rüdiger Schmitz, Peter Thalmann, Simone Hieber, Natalia Chicherova, Philippe Cattin, Felix Beckmann, Julia Herzen, Timm Weitkamp, Till Saxer, Bert Müller

Proceedings Volume 9212, 921203 (2014) https://doi.org/10.1117/12.2060443

KEYWORDS: Arteries, Tissues, X-rays, Tomography, Absorption, Interferometry, Visualization, Phase contrast, Blood circulation, Phase interferometry

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Proceedings Article | 17 October 2012 Paper

Comparison of propagation-based phase-contrast tomography approaches for the evaluation of dentin microstructure

Hans Deyhle, Timm Weitkamp, Sabrina Lang, Georg Schulz, Alexander Rack, Irene Zanette, Bert Müller

Proceedings Volume 8506, 85060N (2012) https://doi.org/10.1117/12.929951

KEYWORDS: Phase contrast, Teeth, X-rays, Image resolution, Tomography, Phase retrieval, Wave propagation, Reconstruction algorithms, Spatial resolution, Absorption

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Proceedings Article | 17 October 2012 Paper

Morphology of atherosclerotic coronary arteries

Margaret Holme, Georg Schulz, Hans Deyhle, Simone Elke Hieber, Timm Weitkamp, Felix Beckmann, Julia Herzen, Johannes Lobrinus, Fabrizio Montecucco, François Mach, Andreas Zumbuehl, Till Saxer, Bert Müller

Proceedings Volume 8506, 850609 (2012) https://doi.org/10.1117/12.930052

KEYWORDS: Polymethylmethacrylate, Visualization, Tissues, Image segmentation, Arteries, Tomography, Computed tomography, Reconstruction algorithms, Absorption, Animal model studies

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Proceedings Article | 17 October 2012 Paper

Comparing the micro-vascular structure of cancerous and healthy tissues

Bert Müller, Sabrina Lang, Felix Beckmann, Marco Dominietto, Markus Rudin, Irene Zanette, Timm Weitkamp, Alexander Rack, Simone Elke Hieber

Proceedings Volume 8506, 850607 (2012) https://doi.org/10.1117/12.929941

KEYWORDS: Phase contrast, Tumors, Tissues, Blood, Image segmentation, Capillaries, Corrosion, Tomography, Data acquisition, Absorption

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Proceedings Article | 17 October 2012 Paper

Asymmetric rotational axis reconstruction of grating-based x-ray phase contrast tomography of the human cerebellum

Georg Schulz, Timm Weitkamp, Irene Zanette, Franz Pfeiffer, Magdalena Müller-Gerbl, Christian David, Bert Müller

Proceedings Volume 8506, 850604 (2012) https://doi.org/10.1117/12.928487

KEYWORDS: Phase contrast, Tissues, Magnetic resonance imaging, X-rays, Interferometry, Tomography, Spatial resolution, Cerebellum, Absorption, Brain

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Proceedings Article | 28 September 2011 Paper

Progress on single crystal beryllium windows

A. Khounsary, B. Lai, A. Rack, S. Goto, O. Chubar, T. Weitkamp

Proceedings Volume 8139, 813914 (2011) https://doi.org/10.1117/12.895391

KEYWORDS: Polishing, Coherence (optics), Sensors, Crystals, X-rays, Charge-coupled devices, Laser crystals, X-ray imaging, Beryllium, Near field optics

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Proceedings Article | 20 September 2010 Paper

Evaluating the microstructure of human brain tissues using synchrotron radiation-based micro-computed tomography

Georg Schulz, Anne Morel, Martha Imholz, Hans Deyhle, Timm Weitkamp, Irene Zanette, Franz Pfeiffer, Christian David, Magdalena Müller-Gerbl, Bert Müller

Proceedings Volume 7804, 78040F (2010) https://doi.org/10.1117/12.859273

KEYWORDS: Phase contrast, Thalamus, Tissues, X-rays, Tomography, Spatial resolution, Neuroimaging, 3D image processing, Absorption, Brain

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Proceedings Article | 3 September 2010 Paper

Recent developments in x-ray Talbot interferometry at ESRF-ID19

Timm Weitkamp, Irene Zanette, Christian David, José Baruchel, Martin Bech, Pascal Bernard, Hans Deyhle, Tilman Donath, Johannes Kenntner, Sabrina Lang, Jürgen Mohr, Bert Müller, Franz Pfeiffer, Elena Reznikova, Simon Rutishauser, Georg Schulz, Arne Tapfer, Jean-Paul Valade

Proceedings Volume 7804, 780406 (2010) https://doi.org/10.1117/12.860203

KEYWORDS: Beam splitters, Phase contrast, Modulation, Interferometers, Sensors, X-rays, Interferometry, Wavefronts, Tomography, Synchrotron radiation

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Proceedings Article | 2 September 2010 Paper

Front- and backside structuring of gratings for phase contrast imaging with x-ray tubes

J. Kenntner, T. Grund, B. Matthis, M. Boerner, J. Mohr, T. Scherer, M. Walter, M. Willner, A. Tapfer, M. Bech, F. Pfeiffer, I. Zanette, T. Weitkamp

Proceedings Volume 7804, 780408 (2010) https://doi.org/10.1117/12.859666

KEYWORDS: Phase contrast, Tissues, Interferometers, X-rays, Tomography, Computed tomography, X-ray imaging, Visibility, Phase shifts, Absorption

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Proceedings Article | 27 August 2010 Paper

Micro-imaging performance of multilayers used as monochromators for coherent hard x-ray synchrotron radiation

A. Rack, T. Weitkamp, M. Riotte, T. Rack, R. Dietsch, T. Holz, M. Krämer, F. Siewert, M. Meduna, Ch. Morawe, P. Cloetens, E. Ziegler

Proceedings Volume 7802, 78020M (2010) https://doi.org/10.1117/12.858355

KEYWORDS: Mirrors, Multilayers, Light sources, Photons, Crystals, Coating, Synchrotron radiation, Monochromators, X-ray imaging, Hard x-rays

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Proceedings Article | 18 September 2008 Paper

High-resolution tomographic imaging of microvessels

Bert Müller, Sabrina Lang, Marco Dominietto, Markus Rudin, Georg Schulz, Hans Deyhle, Marco Germann, Franz Pfeiffer, Christian David, Timm Weitkamp

Proceedings Volume 7078, 70780B (2008) https://doi.org/10.1117/12.794157

KEYWORDS: Cancer, Tumors, Tissues, Blood vessels, Capillaries, X-rays, Tomography, Spatial resolution, Barium, Brain

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Proceedings Article | 16 September 2008 Paper

The high-resolution synchrotron-based imaging stations at the BAMline (BESSY) and TopoTomo (ANKA)

Alexander Rack, Heinrich Riesemeier, Simon Zabler, Timm Weitkamp, Bernd Müller, Gerd Weidemann, Peter Modregger, John Banhart, Lukas Helfen, Andreas Danilewsky, Hans Gräber, Richard Heldele, Boaz Mayzel, Jürgen Goebbels, Tilo Baumbach

Proceedings Volume 7078, 70780X (2008) https://doi.org/10.1117/12.793721

KEYWORDS: Light sources, Cameras, Sensors, Crystals, X-rays, Scintillators, Image resolution, Synchrotrons, Spatial resolution, Monochromators

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Proceedings Article | 7 September 2006 Paper

Tomography with grating interferometers at low-brilliance sources

Timm Weitkamp, Christian David, Christian Kottler, Oliver Bunk, Franz Pfeiffer

Proceedings Volume 6318, 63180S (2006) https://doi.org/10.1117/12.683851

KEYWORDS: Beam splitters, Fringe analysis, Interferometers, Sensors, X-rays, X-ray sources, Wavefronts, Tomography, Visibility, Absorption

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Proceedings Article | 4 November 2004 Paper

Tantalum zone plates for scanning x-ray microscopy between 0.5 and 2.5 keV

Timm Weitkamp, Olivier Dhez, Burkhard Kaulich, Christian David

Proceedings Volume 5539, (2004) https://doi.org/10.1117/12.559704

KEYWORDS: Nanotechnology, Lithography, Photons, Silicon, X-ray microscopy, Chromium, Zone plates, Tantalum, Nanolithography, Diffraction gratings

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Proceedings Article | 26 October 2004 Paper

Nanotomography using parabolic refractive x-ray lenses

Christian Schroer, Boris Benner, Til Florian Gunzler, Marion Kuhlmann, Jens Patommel, Bruno Lengeler, Andrea Somogyi, Timm Weitkamp, Christoph Rau, Anatoly Snigirev, Irina Snigireva

Proceedings Volume 5535, (2004) https://doi.org/10.1117/12.559643

KEYWORDS: Microscopes, Lenses, Sensors, X-rays, X-ray microscopy, Tomography, Spatial resolution, X-ray imaging, Beryllium, Hard x-rays

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Proceedings Article | 26 October 2004 Paper

Hard x-ray phase imaging and tomography with a grating interferometer

Timm Weitkamp, Ana Diaz, Bernd Nohammer, Franz Pfeiffer, Torben Rohbeck, Peter Cloetens, Marco Stampanoni, Christian David

Proceedings Volume 5535, (2004) https://doi.org/10.1117/12.569643

KEYWORDS: Interferometers, Sensors, X-rays, Silicon, Interferometry, Wavefronts, Tomography, Phase imaging, Signal detection, Absorption

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Proceedings Article | 26 October 2004 Paper

Automatic geometrical calibration for x-ray microtomography based on Fourier and Radon analysis

Timm Weitkamp, Pierre Bleuet

Proceedings Volume 5535, (2004) https://doi.org/10.1117/12.557094

KEYWORDS: Radon, Sensors, Calibration, X-rays, Radiography, Image registration, Tomography, Detector arrays, Computed tomography, Synchrotron radiation

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Proceedings Article | 21 October 2004 Paper

XWFP: an x-ray wavefront propagation software package for the IDL computer language

Timm Weitkamp

Proceedings Volume 5536, (2004) https://doi.org/10.1117/12.569642

KEYWORDS: Optical components, X-ray optics, Optical spheres, Lenses, Sensors, X-rays, Wavefronts, Wave propagation, Hard x-rays, Absorption

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Proceedings Article | 18 October 2004 Paper

Moiré interferometry formulas for hard x-ray wavefront sensing

Timm Weitkamp, A. Diaz, Bernd Nohammer, Franz Pfeiffer, Marco Stampanoni, Eric Ziegler, Christian David

Proceedings Volume 5533, (2004) https://doi.org/10.1117/12.559695

KEYWORDS: Fringe analysis, Interferometers, Sensors, X-rays, Wavefront sensors, Wavefronts, Deflectometry, Wavefront distortions, Hard x-rays, Absorption

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