Timm Weitkamp

Dr. Timm Weitkamp

orcid

Research Focus & Metrics

Academic Career Length

28Years (1999-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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26 March 2006 in Nature Physics
Verified
Journal Article
Open access
PDF file
FPFranz Pfeiffer
Franz Pfeiffer
TWTimm Weitkamp
Timm Weitkamp
OBOliver Bunk
Oliver Bunk
CDChristian David
Christian David
X-ray radiographic absorption imaging is an invaluable tool in medical diagnostics and materials science. For biological tissue samples, polymers or fibre composites, however, the use of conventional X-ray radiography is limited due to their weak absorption. This is resolved at highly brilliant X-ray synchrotron or micro-focus sources by using phase-sensitive imaging methods to improve the contrast1,2. However, the requirements of the illuminating radiation mean that hard-X-ray phase-sensitive imaging has until now been impractical with more readily available X-ray sources, such as X-ray tubes. In this letter, we report how a setup consisting of three transmission gratings can efficiently yield quantitative differential phase-contrast images with conventional X-ray tubes. In contrast with existing techniques, the method requires no spatial or temporal coherence, is mechanically robust, and can be scaled up to large fields of view. Our method provides all the benefits of contrast-enhanced phase-sensitive imaging, but is also fully compatible with conventional absorption radiography. It is applicable to X-ray medical imaging, industrial non-destructive testing, and to other low-brilliance radiation, such as neutrons or atoms.

8 August 2005 in Optics Express
Verified
Journal Article
Closed access
PDF file
TWTimm Weitkamp
Timm Weitkamp
ADAna Diaz
Ana Diaz
CDChristian David
Christian David
FPFranz Pfeiffer
Franz Pfeiffer
MSMarco Stampanoni
Marco Stampanoni
EZEric Ziegler
Eric Ziegler
Using a high-efficiency grating interferometer for hard X rays (10–30 keV) and a phase-stepping technique, separate radiographs of the phase and absorption profiles of bulk samples can be obtained from a single set of measurements. Tomographic reconstruction yields quantitative three-dimensional maps of the X-ray refractive index, with a spatial resolution down to a few microns. The method is mechanically robust, requires little spatial coherence and monochromaticity, and can be scaled up to large fields of view, with a detector of correspondingly moderate spatial resolution. These are important prerequisites for use with laboratory X-ray sources.

1 January 2013 in Journal of Nuclear Materials
Verified
Journal Article
Open access
MRMichael Rieth
Michael Rieth
SDS.L. Dudarev
S.L. Dudarev
SVS.M. Gonzalez de Vicente
S.M. Gonzalez de Vicente
JAJ. Aktaa
J. Aktaa
Tommy Ahl­grenTommy Ahl­gren
Tommy Ahl­gren
AZA. Zivelonghi
A. Zivelonghi
The current magnetic confinement nuclear fusion power reactor concepts going beyond ITER are based on assumptions about the availability of materials with extreme mechanical, heat, and neutron load capacity. In Europe, the development of such structural and armour materials together with the necessary production, machining, and fabrication technologies is pursued within the EFDA long-term fusion materials programme. This paper reviews the progress of work within the programme in the area of tungsten and tungsten alloys. Results, conclusions, and future projections are summarized for each of the programme´s main subtopics, which are: (1) fabrication, (2) structural W materials, (3) W armour materials, and (4) materials science and modelling. It gives a detailed overview of the latest results on materials research, fabrication processes, joining options, high heat flux testing, plasticity studies, modelling, and validation experiments

16 March 2011 in Journal of Synchrotron Radiation
Verified
Journal Article
Closed access
PDF file
TWTimm Weitkamp
Timm Weitkamp
DHD. Haas
D. Haas
DWD. Wegrzynek
D. Wegrzynek
ARA. Rack
A. Rack

13 December 1999 in Physical Review Letters
Verified
Journal Article
Closed access
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RMR. H. Mathiesen
R. H. Mathiesen
LAL. Arnberg
L. Arnberg
FMF. Mo
F. Mo
TWTimm Weitkamp
Timm Weitkamp
ASA. Snigirev
A. Snigirev
Direct beam x-ray imaging, with intense coherent monochromatic synchrotron radiation and a fast readout low noise detector has been used for in situ studies of cellular and dendritic solidification of Sn-Pb alloys. Temporal and spatial resolutions down to ∼0.7s and ∼2.5μm, respectively, with a field of view up to 1mm2 were obtained. The collected images display features from both phase and amplitude contrast which, combined with the attainable temporal resolution, provide a method with the potential to uncover dynamic processes in nonequilibrium solidification.

1 August 2002 in Metallurgical and Materials Transactions B
Verified
Journal Article
Closed access
PDF file
RMRagnvald H. Mathiesen
Ragnvald H. Mathiesen
LALars Arnberg
Lars Arnberg
KRKjell Ramsøskar
Kjell Ramsøskar
TWTimm Weitkamp
Timm Weitkamp
CRChristoph Rau
Christoph Rau
ASAnatoly Snigirev
Anatoly Snigirev