Dr. Oliver Bunk

photo of Oliver Bunk

Head of Laboratory for Macromolecules and Bioimaging (LSB)
Deputy Head of Photon Science Division (PSD)

Paul Scherrer Institute
Forschungsstrasse 111
5232 Villigen PSI
Switzerland

See also Clarivate Analytics Web of Science / Publons researcher ID B-7602-2013, Orcid 0000-0001-6563-4053, Scopus Author ID: 8219591600, or Research Gate Oliver_Bunk2. Alternatively you may look at my PSI publications listed in the repository DORA, partially with post-prints.

2019-now
    • Basu S, Olieric V, Leonarski F, Matsugaki N, Kawano Y, Takashi T, et al.
      Long-wavelength native-SAD phasing: opportunities and challenges
      IUCrJ. 2019; 6(3): 1-14. https://doi.org/10.1107/S2052252519002756
      DORA PSI
    • Giannini C, Terzi A, Fusaro L, Sibillano T, Diaz A, Ramella M, et al.
      Scanning X‐ray microdiffraction of decellularized pericardium tissue at increasing glucose concentration
      Journal of Biophotonics. 2019: e201900106 (12 pp.). https://doi.org/10.1002/jbio.201900106
      DORA PSI
    • Giannini C, Ladisa M, Lutz VB, Terzi A, Ramella M, Fusaro L, et al.
      X-ray scanning microscopies of microcalcifications in abdominal aortic and popliteal artery aneurysms
      IUCrJ. 2019; 6: 267-276. https://doi.org/10.1107/S2052252519001544
      DORA PSI
    • Nida S, Tsibizov A, Ziemann T, Woerle J, Moesch A, Schulze-Briese C, et al.
      Silicon carbide X-ray beam position monitors for synchrotron applications
      Journal of Synchrotron Radiation. 2019; 26(1): 28-35. https://doi.org/10.1107/S1600577518014248
      DORA PSI
    2018
    • F. Leonarski, S. Redford, A. Mozzanica, C. Lopez-Cuenca, E. Panepucci, K. Nass, D. Ozerov, L. Vera, V. Olieric, D. Buntschu, R. Schneider, G. Tinti, E. Froejdh, K. Diederichs, O. Bunk, B. Schmitt, and M. Wang, Fast and accurate data collection for macromolecular crystallography using the JUNGFRAU detector Nature Methods 15, 799 (2018). abstract on journal page
    • H. Deyhle, S.N. White, L. Botta, M. Liebi, M. Guizar-Sicairos, O. Bunk, and B. Müller, Automated Analysis of Spatially Resolved X-ray Scattering and Micro Computed Tomography of Artificial and Natural Enamel Carious Lesions J. Imaging 4, 81 (2018). abstract and open-access article on journal page
    • J. C. da Silva, M. Guizar-Sicairos, M. Holler, A. Diaz, J.A. van Bokhoven, O. Bunk, and A. Menzel, Quantitative region-of-interest tomography using variable field of view Optics Express 26, 16752 (2018). abstract and open-access article on journal page
    • M. Holler, J. Raabe, A. Diaz, M. Guizar-Sicairos, R. Wepf, M. Odstrcil, F.R. Shaik, V. Panneels, A. Menzel, B. Sarafimov, S. Maag, X. Wang, V. Thominet, H. Walther, T. Lachat, M. Vitins, and O. Bunk, OMNY-A tOMography Nano crYo stage Rev. Sci. Instrum. 89, 043706 (2018). abstract on journal page
    • M. Liebi, M. Georgiadis, J. Kohlbrecher, M. Holler, J. Raabe, I. Usov, A. Menzel, P. Schneider, O. Bunk, and M. Guizar-Sicairos, Small-angle X-ray scattering tensor tomography: model of the three-dimensional reciprocal-space map, reconstruction algorithm and angular sampling requirements, Acta Cryst. A74, 12-24 (2018). abstract and open-access article on journal page
    2017
    • A. Gourrier , C. Chadefaux, E. Lemaitre, L. Bellot-Gurlet, M. Reynolds, M. Burghammer, M. Plazanet, G. Boivin, D. Farlay, O. Bunk, and I. Reiche, Nanoscale modifications in the early heating stages of bone are heterogeneous at the microstructural scale, PLoS ONE 12, e0176179 (2017). abstract and open-access article on journal page
    • M. Holler, M. Guizar-Sicairos, E.H.R. Tsai, R. Dinapoli, E. Müller, O. Bunk, J. Raabe, G. Aeppli, High-resolution non-destructive three-dimensional imaging of integrated circuits , Nature 543, 402 (2017). abstract on journal page
    2016
    • A. Casanas, R. Warshamanage, A. D. Finke, E. Panepucci, V. Olieric, A. Nöll, R. Tampé, S. Brandstetter, A. Förster, M. Mueller, C. Schulze-Briese, O. Bunk, and M. Wang, EIGER detector: application in macromolecular crystallography, Acta Cryst. D 72, 1036–1048 (2016). abstract and open-access article on journal page
    • M. Georgiadis, M. Guizar-Sicairos, O. Gschwend, P. Hangartner, O. Bunk, R. Müller, and P. Schneider, Ultrastructure organization of human trabeculae assessed by 3D sSAXS and relation to bone microarchitecture, PLoS ONE 11, e0159838 (2016). abstract and open-access article on journal page
    • T. Sibillano, L. De Caro, F. Scattarella, G. Scarcelli, D. Siliqi, D. Altamura, M. Liebi, M. Ladisa, O. Bunk, and C. Giannini, Interfibrillar packing of bovine cornea by table-top and synchrotron scanning SAXS microscopy, J. Appl. Cryst. 49, 1231-1239 (2016). abstract on journal page
    • J.A. Wojdyla, E. Panepucci, I. Martiel, S. Ebner, C.-Y. Huang, M. Caffrey, O. Bunk, and M. Wang, Fast two-dimensional grid and transmission X-ray microscopy scanning methods for visualizing and characterizing protein crystals, J. Appl. Cryst. 49, 944-952 (2016). abstract and open-access article on journal page
    2015
    • A. Diaz, B. Malkova, M. Holler, M. Guizar-Sicairos, E. Lima, V. Panneels, G. Pigino, A.G. Bittermann, L. Wettstein, T. Tomizaki, O. Bunk, G. Schertler, T. Ishikawa, R. Wepf, A. Menzel, Three-dimensional mass density mapping of cellular ultrastructure by ptychographic X-ray nanotomography, J. Struct. Biol. 192, 461–469 (2015). abstract and open-access PDF file on journal page. Addendum in J. Struct. Biol. 193, 83 (2016) addendum on journal page
    • M. Liebi, M. Georgiadis, A. Menzel, P. Schneider, J. Kohlbrecher, O. Bunk, M. Guizar-Sicairos, Nanostructure surveys of macroscopic specimens by small-angle scattering tensor tomography, Nature 527, 349-352 (2015). abstract on journal page
    • J.C. da Silva, P. Trtik, A. Diaz, M. Holler, M. Guizar-Sicairos, J. Raabe, O. Bunk, and A. Menzel, Mass Density and Water Content of Saturated Never-Dried Calcium Silicate Hydrates, Langmuir 31, 3779-3783 (2015). abstract and open-access PDF file on journal page
    • M. Guizar-Sicairos, J.J. Boon, K. Mader, A. Diaz, A. Menzel, and O. Bunk, Quantitative interior x-ray nanotomography by a hybrid imaging technique, Optica 2, 259-266 (2015). abstract and open-access PDF file on journal page
    • M. Georgiadis, M. Guizar-Sicairos, A. Zwahlen, A.J. Trüssel, O. Bunk, R. Müller, P. Schneider, 3D scanning SAXS: A novel method for the assessment of bone ultrastructure orientation, Bone 71, 42-52 (2015). abstract on journal page
    2014
    • M. Guizar-Sicairos, I. Johnson, A. Diaz, M. Holler, P. Karvinen, H.-C. Stadler, R. Dinapoli, O. Bunk, and A. Menzel, High-throughput ptychography using Eiger: scanning X-ray nano-imaging of extended regions, Opt. Express 22, 14859-14870 (2014). abstract and open-access PDF file on journal page
    • M. Stampanoni, A. Menzel, B. Watts, K. Mader, and O. Bunk, Coherent X-ray Imaging: Bridging the Gap between Atomic and Micro-scale Investigations Chimia, 68 66-72 (2014). abstract on journal page
    • M. Holler, A. Diaz, M. Guizar-Sicairos, P. Karvinen, E. Färm, M. Härkönen, M. Ritala, A. Menzel, J. Raabe, and O. Bunk, X-ray ptychographic computed tomography at 16 nm isotropic 3D resolution, Scientific Reports 4, 3857 (2014). abstract and open-access PDF file on journal page
    • C. Giannini, D. Siliqi, M. Ladisa, D. Altamura, A. Diaz, A. Beraudi, T. Sibillano, L. De Caro, S. Stea, F. Baruffaldi, and O. Bunk, Scanning SAXS-WAXS microscopy on osteoarthritis-affected bone - an age-related study J. Appl. Cryst. 47, 1-8 (2014). abstract on journal page
    • A. Diaz, A. Guizar-Sicairos, A. Poeppel, A. Menzel, and O. Bunk, Characterization of carbon fibers using x-ray phase nanotomography, Carbon 67, 98-103 (2014). abstract and open-access PDF file on journal page
    • H. Deyhle, S.N. White, O. Bunk, F. Beckmann, and B. Müller, Nanostructure of the carious tooth enamel lesion, Acta Biomater. 10, 355-364 (2014). abstract on journal page
    • F. Berenguer, R.J. Bean, L. Bozec, J. Vila-Comamala, F. Zhang, C. M. Kewish, O. Bunk, J.M. Rodenburg, and I.K. Robinson, Coherent X-ray imaging of collagen fibril distributions within intact tendons, Biophys.J. 106, 459-466 (2014). abstract on journal page
    2013
    • U. Gasser, J.-J. Lietor-Santos, A. Scotti, O. Bunk, A. Menzel, and A. Fernandez-Nieves, Transient formation of bcc crystals in suspensions of poly(N-isopropylacrylamide)-based microgels, Phys. Rev. E 88, 052308 (2013). abstract on journal page
    • M. Iannuzzi, I. Kalichava, H. Ma, S.J. Leake, H. Zhou, G. Li, Y. Zhang, O. Bunk, H. Gao, J. Hutter, P.R. Willmott, and T. Greber, Moiré beatings in graphene on Ru(0001), Phys. Rev. B 88, 125433 (2013). abstract on journal page
    • C. Grünzweig, J. Kopecek, B. Betz, A. Kaestner, K. Jefimovs, J. Kohlbrecher, U. Gasser, O. Bunk, C. David, T. Donath, and F. Pfeiffer, Quantification of the neutron darkfield imaging signal in grating interferometry, Phys. Rev. B 88, 125104 (2013). abstract on journal pagee
    • I. Olliges-Stadler, M.D. Rossell, M. Süess, B. Ludi, O. Bunk, J. S. Pedersen, H. Birkedal, and M. Niederberger, A comprehensive study of the crystallization mechanism involved in the nonaqueous formation of tungstite, Nanoscale 5, 8517-8525 (2013). abstract on journal page
    • L. De Caro, D. Altamura, T. Sibillano, D. Siliqi, G. Filograsso, O. Bunk, and C. Giannini, Rat-tail tendon fiber SAXS high-order diffraction peaks recovered by a superbright laboratory source and a novel restoration algorithm, J. Appl. Cryst. 46, 672-678 (2013). abstract on journal page
    • P. Trtik, A. Diaz, M. Guizar-Sicairos, A. Menzel, and O. Bunk, Density mapping of hardened cement paste using ptychographic X-ray computed tomography, Cem. Con. Comp. 36, 71-77 (2013). abstract on journal page
    • E. Perret, F.A. Reifler, R. Hufenus, O. Bunk, and M. Heuberger, Modified Crystallization in PET/PPS Bicomponent Fibers Revealed by Small-Angle and Wide-Angle X-ray Scattering, Macromolecules 46, 440 (2013). abstract on journal page
    2012
    • M. Guizar-Sicairos, M. Holler, A. Diaz, J. Vila-Comamala, O. Bunk, and A. Menzel, Role of the illumination spatial-frequency spectrum for ptychography, Phys. Rev. B. 86, 100103(R) (2012). abstract on journal page
    • M. Holler, J. Raabe, A. Diaz, M. Guizar-Sicairos, C. Quitmann, A. Menzel, and O. Bunk, An instrument for 3D x-ray nano-imaging, Rev. Sci. Instrum. 83, 073703 (2012). abstract and open-access PDF file on journal page
    • S. Rutishauser, L. Samoylova, J. Krzywinski, O. Bunk, J. Grünert, H. Sinn, M. Cammarata, D.M. Fritz, and C. David, Exploring the wavefront of hard X-ray free-electron laser radiation, Nature Comm. 3, 947 (2012). abstract on journal page
    • C. Giannini, D. Siliqi, O. Bunk, A. Beraudi, M. Ladisa, D. Altamura, S. Stea, and F. Baruffaldi, Correlative Light and Scanning X-Ray Scattering Microscopy of Healthy and Pathologic Human Bone Sections, Sci. Rep. 2, 435 (2012). abstract and open-access PDF file on journal page
    • J. Althaus, H. Deyhle, O. Bunk, P.M. Kristiansen, and B. Müller, Anisotropy in polyetheretherketone films, J. Nanophoton. 6, 063510 (2012). abstract on journal page
    • P. Urwyler, H. Deyhle, O. Bunk, P.M. Kristiansen, and B. Müller, Nanometer-size anisotropy of injection-molded polymer micro-cantilever arrays J. Appl. Phys. 111, 103530 (2012). abstract on journal page
    • A. Diaz, P. Trtik, M. Guizar-Sicairos, A. Menzel, P. Thibault, and O. Bunk, Quantitative x-ray phase nanotomography, Phys. Rev. B. 85, 020104(R) (2012). abstract on journal page
    • S. Gaiser, H. Deyhle, O. Bunk, S.N. White, B. Müller, Understanding nano-anatomy of healthy and carious human teeth: a prerequisite for nanodentistry, Biointerphases 7, 4 (2012). abstract and open-access PDF file on journal page
    • K. Nygård, S.P. Delcambre, D.K. Satapathy, O. Bunk, P.F. Nealey, and J.F. van der Veen, Size-Dependent Shape Evolution of Patterned Polymer Films Studied in Situ by Phase-Retrieval-Based Small-Angle X-ray Scattering, Macromolecules 45, 5798-5805 (2012). abstract on journal page
    • S. Chodankar, E. Perret, K. Nygård, O. Bunk, D.K. Satapathy, R.M.E. Marzal, T.E. Balmer, M. Heuberger, J.F. van der Veen, Density profile of water in nanoslit. EPL 99, 26001 (2012). abstract on journal page
    • G. Liu, A. Ramírez-Hernández, H. Yoshida, K. Nygård, D.K. Satapathy, O. Bunk, J.J. de Pablo, and P.F. Nealey, Morphology of Lamellae-Forming Block Copolymer Films between Two Orthogonal Chemically Nanopatterned Striped Surfaces, Phys. Rev. Lett. 108, 065502 (2012). abstract on journal page
    • M. Bech, S. Schleede, G. Potdevin, K. Achterhold, O. Bunk, T.H. Jensen, R. Loewen, R. Ruth, and Franz Pfeiffer, Experimental validation of image contrast correlation between ultra-small-angle X-ray scattering and grating-based dark-field imaging using a laser-driven compact X-ray source, Photon. Lasers Med. 1 47-50 (2012). abstract on journal page
    2011
    • H. Deyhle, O. Bunk, and B. Müller, Nanostructure of healthy and caries-affected human teeth, Nanomedicine: NBM 7, 694-701 (2011). abstract on journal page
    • M. Guizar-Sicairos, A. Diaz, M. Holler, M.S. Lucas, A. Menzel, R.A. Wepf, and O. Bunk, Phase tomography from x-ray coherent diffractive imaging projections, Optics Express 19, 21345-21357 (2011). abstract and open-access PDF file on journal page
    • J. Vila-Comamala, A. Diaz, M. Guizar-Sicairos, A. Mantion, C.M. Kewish, A. Menzel, O. Bunk, and C. David, Characterization of high-resolution diffractive X-ray optics by ptychographic coherent diffractive imaging, Optics Express 19, 21333-21344 (2011). abstract and open-access PDF file on journal page
    • C. David, S. Gorelick, S. Rutishauser, J. Krzywinski, J. Vila-Comamala, V.A. Guzenko, O. Bunk, E. Färm, M. Ritala, M. Cammarata, D.M. Fritz, R. Barrett, L. Samoylova, J. Grünert, and H. Sinn, Nanofocusing of hard x-ray free electron laser pulses using diamond based Fresnel zone plates, Nature Sci. Rep. 1, 57 (2011). abstract and open-access PDF file on journal page
    • T.H. Jensen, M. Bech, O. Bunk, A. Menzel, A. Bouchet, G. Le Duc, R. Feidenhans'l, and F. Pfeiffer, Molecular X-ray computed tomography of myelin in a rat brain, NeuroImage 57, 124-129 (2011). abstract on journal page
    • T.H. Jensen, M. Bech, O. Bunk, M. Thomsen, A. Menzel, A. Bouchet, G. Le Duc, R. Feidenhans'l, and F. Pfeiffer, Brain tumor imaging using small-angle x-ray scattering tomography, Phys. Med. Biol. 56, 1717-1726 (2011). abstract on journal page
    • M. Chabior, T. Donath, C. David, O. Bunk, M. Schuster, C. Schroer, and F. Pfeiffer, Beam hardening effects in grating-based x-ray phase-contrast imaging, Med. Phys. 38, 1189-1195 (2011). abstract on journal page
    2010
    • C.M. Kewish, M. Guizar-Sicairos, C. Liu, J. Qian, B. Shi, C. Benson, A.M. Khounsary, J. Vila-Comamala, O. Bunk, J.R. Fienup, A.T. Macrander, and L. Assoufid, Reconstruction of an astigmatic hard X-ray beam and alignment of K-B mirrors from ptychographic coherent diffraction data, Optics Express 18, 23420-23427 (2010). abstract and open-access PDF file on journal page
    • P. Huber, O. Bunk, U. Pietsch, M. Textor, and T. Geue, Grazing Incidence Small Angle X-ray Scattering on Colloidal Crystals, J. Phys. Chem. B 114, 12473-12479 (2010). abstract on journal page
    • M. Dierolf, A. Menzel, P. Thibault, P. Schneider, C.M. Kewish, R. Wepf, O. Bunk, and F. Pfeiffer, Ptychographic X-ray computed tomography at the nanoscale, Nature 467, 436-439 (2010). abstract on journal page
    • M. Bech, O. Bunk, T. Donath, R. Feidenhans'l, C. David, and F. Pfeiffer, Quantitative x-ray dark-field computed tomography, Phys. Med. Biol. 55, 5529-5539 (2010). abstract on journal page
    • K. Nygård, D.K. Satapathy, E. Perret, C. Padeste, O. Bunk, C. David, and J.F. van der Veen, Surface-specific ordering of reverse micelles in confinement, Soft Matter 6, 4536-4539 (2010). abstract on journal page
    • C. Deiter, M. Bierkandt, A. Klust, C. Kumpf, Y. Su, O. Bunk, R. Feidenhans'l, and J. Wollschläger, Structural transitions and relaxation processes during the epitaxial growth of ultrathin CaF2 films on Si(111) Phys. Rev. B. 82, 085449 (2010). abstract on journal page
    • B.R. Pauw, M.E. Vigild, K. Mortensen, J.W. Andreasen, E.A. Klop, D.W. Breiby, and O. Bunk, Strain-induced internal fibrillation in looped aramid filaments, Polymer 51, 4589-4598 (2010). abstract on journal page
    • A. Menzel, C.M. Kewish, P. Kraft, B. Henrich, K. Jefimovs, J. Vila-Comamala, C. David, M. Dierolf, P. Thibault, F. Pfeiffer, and O. Bunk, Scanning transmission X-ray microscopy with a fast framing pixel detector, Ultramicroscopy 110, 1143-1147 (2010). abstract on journal page
    • E. Perret, K. Nygård, D.K Satapathy, T.E. Balmer, O. Bunk, M. Heuberger, and J.F. van der Veen, X-ray reflectivity theory for determining the density profile of a liquid under nanometre confinement, J. Synchrotron Rad. 17 465-472 (2010). abstract on journal page
    • E. Perret, K. Nygård, D.K Satapathy, T.E. Balmer, O. Bunk, M. Heuberger, and J.F. van der Veen, Molecular liquid under nanometre confinement: density profiles underlying oscillatory forces, J. Phys Condens. Matter 22, 235102 (2010). abstract on journal page
    • M. Dierolf, P. Thibault, A. Menzel, C.M. Kewish, K. Jefimovs, I. Schlichting, K. von König, O. Bunk, and F. Pfeiffer, Ptychographic coherent diffractive imaging of weakly scattering specimens, New J. Phys. 12, 035017 (2010). abstract and open-access PDF file on journal page
    • C. M. Kewish, P. Thibault, O. Bunk, and F. Pfeiffer, The potential for two-dimensional crystallography of membrane proteins at future x-ray free-electron laser sources, New J. Phys. 12, 035005 (2010). abstract and open-access PDF file on journal page
    • T. H. Jensen, M. Bech, O. Bunk, T. Donath, C. David, R. Feidenhans'l, and F. Pfeiffer, Directional x-ray dark-field imaging, Phys. Med. Biol. 55, 3317-3323 (2010). abstract on journal page
    • B. Müller, H. Deyhle, D.A. Bradley, M. Farquharson, G. Schulz, M. Müller-Gerbl, and O. Bunk, Scanning X-ray scattering: Evaluating the nanostructure of human tissues, European Journal of Nanomedicine 3, 30-33 (2010). volume on journal page
    • T. Donath, F. Pfeiffer, O. Bunk, C. Grünzweig, E. Hempel, S. Popescu, P. Vock, and C. David, Toward clinical x-ray phase-contrast CT-demonstration of enhanced soft-tissue contrast in human specimen, Invest. Radiol. 45, 445-452 (2010). abstract on journal page DOI link
    • P.A. Brühwiler, M. Barbezat, A. Necola, D.J. Kohls, O. Bunk, D.W. Schaefer, P. Pötschke, Comparison of quasistatic to impact mechanical properties of multiwall carbon nanotube/polycarbonate composites, J. Mater. Res. 25, 1118-1130 (2010). abstract on journal page
    • K. Nygård, O. Bunk, E. Perret, C. David, and J. F. van der Veen, Diffraction gratings as small-angle x-ray scattering calibration standards, J. Appl. Cryst. 43, 350 (2010). abstract on journal page
    • C.M. Kewish, P. Thibault, M. Dierolf, O. Bunk, A. Menzel, J. Vila-Comamala, K. Jefimovs, and F. Pfeiffer, Ptychographic characterization of the wavefield in the focus of reflective hard X-ray optics, Ultramicroscopy 110, 325-329 (2010). abstract on journal page
    • P. Kraft, O. Bunk, F.A. Reifler, R. Hufenus, M. Heuberger, and F. Pfeiffer, One-dimensional small-angle x-ray scattering tomography of dip-coated polyamide 6 monofilaments, J. Synchrotron Rad. 17, 257 (2010). abstract on journal page
    • C. Grünzweig, C. David, O. Bunk, J. Kohlbrecher, E. Lehmann, Y. W. Lai, R. Schäfer, S. Roth, P. Lejcek, J. Kopecek, and F. Pfeiffer, Visualizing the propagation of volume magnetization in bulk ferromagnetic materials by neutron grating interferometry, J. Appl. Phys. 107 09D308 (2010). abstract on journal page
    2009
    • O. Bunk, M. Bech, T.H. Jensen, R. Feidenhans'l, T. Binderup, A. Menzel, and F. Pfeiffer, Multimodal x-ray scatter imaging, New J. Phys. 11, 123016 (2009). abstract and open-access PDF file on journal page
    • P. Thibault, M. Dierolf, C.M. Kewish, A. Menzel, O. Bunk, and F. Pfeiffer, Contrast mechanisms in scanning transmission x-ray microscopy, Phys. Rev. A 80, 043813 (2009). abstract on journal page
    • K. Nygård, D.K. Satapathy, O. Bunk, E. Perret, J. Buitenhuis, C. David, and J.F. van der Veen, Grating-based holographic X-ray diffraction: theory and application to confined fluids, J. Appl. Cryst. 42, 1129-1138 (2009). abstract on journal page
    • E. Perret, K. Nygård, D.K. Satapathy, T.E. Balmer, O. Bunk, M. Heuberger, and J.F. van der Veen, X-ray reflectivity reveals equilibrium density profile of molecular liquid under nanometre confinement, EPL 88, 36004 (2009). abstract on journal page
    • T. Donath, M. Chabior, F. Pfeiffer, O. Bunk, E. Reznikova, J, Mohr, E, Hempel, S, Popescu, M, Hoheisel, M, Schuster, J. Baumann, and C. David, Inverse geometry for grating-based x-ray phase-contrast imaging, J. Appl. Phys. 106, 054703 (2009). abstract on journal page
    • D.K. Satapathy, K. Nygård, O. Bunk, K. Jefimovs, E. Perret, A. Diaz, F. Pfeiffer, C. David, and J.F. van der Veen, Buckling and layering transitions in confined colloids, EPL 87, 34001 (2009). abstract on journal page
    • K. Nygård, D.K. Satapathy, J. Buitenhuis, E. Perret, O. Bunk, C. David, and J.F. van der Veen, Confinement-induced orientational alignment of quasi-2D fluids, EPL 86, 66001 (2009). abstract on journal page
    • T. Donath, F. Pfeiffer, O. Bunk, W. Groot, M. Bednarzik, C. Grünzweig, E. Hempel, S. Popescu, M. Hoheisel, and C. David, Phase-contrast imaging and tomography at 60 keV using a conventional x-ray tube source, Rev. Sci. Instrum. 80, 053701 (2009). abstract on journal page
    • J. Herzen, T. Donath, F. Pfeiffer, O. Bunk, C. Padeste, F. Beckmann, A. Schreyer, and C. David, Quantitative phase-contrast tomography of a liquid phantom using a conventional x-ray tube source, Optics Express 17, 10010-10018 (2009). abstract and open-access PDF file on journal page
    • F. Pfeiffer, M. Bech, O. Bunk, T. Donath, B. Henrich, P. Kraft, and C. David, X-ray dark-field and phase-contrast imaging using a grating interferometer, J. Appl. Phys. 105, 102006 (2009). abstract on journal page
    • M. Bech, T.H. Jensen, R. Feidenhans'l, O. Bunk, C. David, and F. Pfeiffer, Soft-tissue phase-contrast tomography with an x-ray tube source, Phys. Med. Biol. 54, 2747-2753 (2009). abstract on journal page
    • P. Thibault, M. Dierolf, O. Bunk, A. Menzel, and Franz Pfeiffer, Probe retrieval in ptychographic coherent diffractive imaging, Ultramicroscopy 109,338-343 (2009). abstract on journal page
    • M. Bech, O. Bunk, C. David, R. Ruth, J. Rifkin, R. Loewen, R. Feidenhans'l and F. Pfeiffer, Hard X-ray phase-contrast imaging with the Compact Light Source based on inverse Compton X-rays, J. Synchrotron Rad. 16, 43-48 (2009). abstract on journal page
    • I. Johnson, Z. Sadygov, O. Bunk, A. Menzel, F. Pfeiffer, and D. Renker, A Geiger-mode avalanche photodiode array for X-ray photon correlation spectroscopy, J. Synchrotron Rad. 16, 105-109 (2009). abstract on journal page
    2008
    • K. Nygård, D.K. Satapathy, O. Bunk, A. Diaz, E. Perret, J. Buitenhuis, F. Pfeiffer, C. David, and J. F. van der Veen, Structure of confined fluids by x-ray interferometry using diffraction gratings, Optics Express 16, 20522-20529 (2008). abstract and open-access PDF file on journal page
    • K.O. Stuen, C. Liu, A.M. Welander, G. Liu, J.J. de Pablo, P.F. Nealey, D.K. Satapathy, K. Nygård, O. Bunk, H.H. Solak, and J.F. van der Veen, In situ characterization of block copolymer ordering on chemically nanopatterned surfaces by time-resolved small angle x-ray scattering, J. Vac. Sci. Technol. B 26, 2504-2508 (2008). abstract on journal page
    • T. Weitkamp, C. David, O. Bunk, J. Bruder, P. Cloetens, and F. Pfeiffer, X-ray phase radiography and tomography of soft tissue using grating interferometry, European Journal of Radiology 68S, 13-17 (2008). abstract on journal page
    • O. Bunk, D.K. Satapathy, F. Pfeiffer, A. Diaz, C. David, K. Nygård, E. Perret, C. Padeste, P.R. Willmott, B.D. Patterson, B. Schmitt, and J.F. van der Veen, Concentration Profiles of Colloidal Fluids in One-Dimensional Confinement, Chimia 62, 789-792 (2008). abstract on journal page
    • F. Pfeiffer, C. David, O. Bunk, T. Donath, M. Bech, G. Le Duc, A. Bravin, and P. Cloetens, Region-of-Interest Tomography for Grating-Based X-Ray Differential Phase-Contrast Imaging, Phys. Rev. Lett. 101, 168101 (2008). abstract on journal page
    • M. Engelhardt, C. Kottler, O. Bunk, C. David, C. Schroer, J. Baumann, M. Schuster, and F. Pfeiffer, The fractional Talbot effect in differential x-ray phase-contrast imaging for extended and polychromatic x-ray sources, J. Microsc. 232, 145-157 (2008). abstract on journal page
    • D.K. Satapathy, O. Bunk, K. Jefimovs, K. Nygård, H. Guo, A. Diaz, E. Perret, F. Pfeiffer, C. David, G. H. Wegdam, and J. F. van der Veen, Colloidal Monolayer Trapped near a Charged Wall: A Synchrotron X-Ray Diffraction Study, Phys. Rev. Lett. 101, 136103 (2008). abstract on journal page
    • P. Thibault, M. Dierolf, A. Menzel, O. Bunk, C. David, and F. Pfeiffer, High-Resolution Scanning X-ray Diffraction Microscopy, Science 321, 379-382 (2008). abstract on journal page
    • C. Grünzweig, C. David, O. Bunk, M. Dierolf, G. Frei, G. Kühne, R. Schäfer, S. Pofahl, H.M.R. Rønnow, and F. Pfeiffer, Bulk magnetic domain structures visualized by neutron dark-field imaging, Appl. Phys. Lett. 93, 112504 (2008). abstract on journal page
    • C. Grünzweig, C. David, O. Bunk, M. Dierolf, G. Frei, G. Kühne, J. Kohlbrecher, R. Schäfer, P. Lejcek, H.M.R. Rønnow, and F. Pfeiffer, Neutron Decoherence Imaging for Visualizing Bulk Magnetic Domain Structures, Phys. Rev. Lett. 101, 025504 (2008). abstract on journal page
    • K. Nygård, D.K. Satapathy, O. Bunk, F. Pfeiffer, C. David, and J. F. van der Veen, Dynamical theory for diffractive x-ray imaging of one-dimensional periodic objects, Appl. Phys. Lett. 92, 214105 (2008). abstract on journal page
    • C. Grünzweig, F. Pfeiffer, O. Bunk, T. Donath, G. Kühne, G. Frei, M. Dierolf, and C. David, Design, fabrication, and characterization of diffraction gratings for neutron phase contrast imaging, Rev. Sci. Instrum. 79, 053703 (2008). abstract on journal page
    • I. Johnson, K. Jefimovs, O. Bunk, C. David, M. Dierolf, J. Gray, D. Renker, and F. Pfeiffer, Coherent Diffractive Imaging Using Phase Front Modifications, Phys. Rev. Lett. 100, 155503 (2008). abstract on journal page
    • O. Bunk, M. Dierolf, S. Kynde, I. Johnson, O. Marti, and F. Pfeiffer, Influence of the overlap parameter on the convergence of the ptychographical iterative engine, Ultramicroscopy 108, 481-487 (2008). abstract on journal page
    • M. Bech, O. Bunk, C. David, P. Kraft, C. Brönnimann, E.F. Eikenberry, and F. Pfeiffer, X-ray imaging with the PILATUS 100k detector, Appl. Rad. Isot. 66, 474-478 (2008). abstract on journal page
    • D.W. Breiby, O. Bunk, J.W. Andreasen, H.T. Lemke, and M.M. Nielsen, Simulating X-ray diffraction of textured films, J. Appl. Cryst. 41, 262-271 (2008). abstract on journal page
    • F. Pfeiffer, M. Bech, O. Bunk, P. Kraft, E.F. Eikenberry, Ch. Brönnimann, C. Grünzweig, and C. David Hard-X-ray dark-field imaging using a grating interferometer, Nature Materials 7, 134-137 (2008). abstract on journal page
    2007
    • R. Herger, P.R. Willmott, O. Bunk, C.M. Schlepütz, B.D. Patterson, B. Delley, V. L. Shneerson, P. F. Lyman, and D. K. Saldin Surface structure of SrTiO3(001), Phys. Rev. B 76, 195435 (2007). abstract on journal page
    • F. Pfeiffer, O. Bunk, C. David, M. Bech, G. Le Duc, A. Bravin, and P. Cloetens, High-resolution brain tumor visualization using three-dimensional x-ray phase contrast tomography, Phys. Med. Biol. 52, 6923-6930 (2007). abstract on journal page
    • M. Engelhardt, J. Baumann, M. Schuster, C. Kottler, F. Pfeiffer, O. Bunk, and C. David, Inspection of refractive x-ray lenses using high-resolution differential phase contrast imaging with a microfocus x-ray source, Rev. Sci. Instrum. 78, 093707 (2007). abstract on journal page
    • F. Pfeiffer, O. Bunk, C. Kottler, and C. David, Tomographic reconstruction of three-dimensional objects from hard X-ray differential phase contrast projection images, Nucl. Instr. Meth. in Phys. Res. A 580, 925-928 (2007). abstract on journal page
    • C. David, T. Weitkamp, F. Pfeiffer, A. Diaz, J. Bruder, T. Rohbeck, A. Groso, O. Bunk, M. Stampanoni, P. Cloetens, Hard X-ray phase imaging and tomography using a grating interferometer, Spectrochimica Acta B 62, 626-630 (2007). abstract on journal page
    • C. Kottler, F. Pfeiffer, O. Bunk, C. Grünzweig, J. Bruder, R. Kaufmann, L. Tlustos, H. Walt, I. Briod, T. Weitkamp, and C. David, Phase contrast X-ray imaging of large samples using an incoherent laboratory source, phys. stat. sol. (a) 204, 2728-2733 (2007). abstract on journal page
    • O. Bunk, A. Diaz, F. Pfeiffer, C. David, B. Schmitt, D.K. Satapathy, and J.F. van der Veen, Diffractive imaging for periodic samples: retrieving one-dimensional concentration profiles across microfluidic channels, Acta Cryst. A 63, 306-314 (2007). abstract on journal page
    • M. Engelhardt, J. Baumann, M. Schuster, C. Kottler, F. Pfeiffer, O. Bunk, and C. David, High-resolution differential phase contrast imaging using a magnifying projection geometry with a microfocus x-ray source, Appl. Phys. Lett. 90, 224101 (2007). abstract on journal page
    • K. Jefimovs, O. Bunk, F. Pfeiffer, D. Grolimund, J.F. van der Veen, and C. David, Fabrication of Fresnel zone plates for hard X-rays, Microelectron. Eng. 84, 1467-1470 (2007). abstract on journal page
    • C. David, J. Bruder, T. Rohbeck, C. Grünzweig, C. Kottler, A. Diaz, O. Bunk, and F. Pfeiffer, Fabrication of diffraction gratings for hard X-ray phase contrast imaging, Microelectron. Eng. 84, 1172-1177 (2007). abstract on journal page
    • C. Kottler, F. Pfeiffer, O. Bunk, C. Grünzweig, and C. David, Grating interferometer based scanning setup for hard x-ray phase contrast imaging, Rev. Sci. Instrum. 78, 043710 (2007). abstract on journal page
    • F. Pfeiffer, C. Kottler, O. Bunk, C. David, Hard x-ray phase tomography with low-brilliance sources, Phys. Rev. Lett., 98, 108105 (2007). abstract on journal page
    • R. Herger, P.R. Willmott, O. Bunk, C.M. Schlepütz, B.D. Patterson, and B. Delley, Surface of strontium titanate, Phys. Rev. Lett. 98, 076102 (2007). abstract on journal page
    • O. Bunk, A. Diaz, F. Pfeiffer, C. David, C. Padeste, H. Keymeulen, P.R. Willmott, B.D. Patterson, B. Schmitt, D.K. Satapathy, J.F. van der Veen, H. Guo, and G.H. Wegdam, Confinement-induced liquid ordering investigated by x-ray phase retrieval, Phys. Rev. E 75, 021501 (2007). abstract on journal page
    • C. Kottler, C. David, F. Pfeiffer, and O. Bunk, A two-directional approach for grating based differential phase contrast imaging using hard x-rays, Optics Express 15, 1175-1181 (2007). abstract and open-access PDF file on journal page
    • O. Bunk, M. Corso, D. Martoccia, R. Herger, P.R. Willmott, B.D. Patterson, J. Osterwalder, J.F. van der Veen, and T. Greber, Surface X-ray diffraction study of boron-nitride nanomesh in air, Surf. Sci. 601, L7-L10 (2007). abstract on journal page
    • J.M. Rodenburg, A.C. Hurst, A.G. Cullis, B.R. Dobson, F. Pfeiffer, O. Bunk, C. David, K. Jefimovs, and I. Johnson, Hard-X-Ray Lensless Imaging of Extended Objects, Phys. Rev. Lett. 98, 034801 (2007). abstract on journal page
    2006
    • F. Pfeiffer, C. Grünzweig, O. Bunk, G. Frei, E. Lehmann, and C. David, Neutron phase imaging and tomography, Phys. Rev. Lett. 96, 215505 (2006) abstract on journal page, Erratum, Phys. Rev. Lett. 97, 069905(E) (2006). abstract on journal page
    • F. Pfeiffer, T. Weitkamp, O. Bunk, and C. David, Phase retrieval and differential phase-contrast imaging with low-brilliance x-ray sources, Nature Phys. 2, 258 (2006). abstract on journal page
    • J. Ciston, L.D. Marks, R. Feidenhans'l, O. Bunk, G. Falkenberg, E.M. Lauridsen, Experimental surface charge density of the Si(100)-2×1H surface, Phys. Rev. B 74, 085401 (2006). abstract on journal page
    • J. Dalmas, H. Oughaddou, C. Léandri, J.-M. Gay, G. Le Lay, G. Tréglia, B. Aufray, O. Bunk, and R.L. Johnson, Formation of an unexpected ordered two-dimensional Ag2Pb surfacealloy on Ag(111): A SXRD and STM study J. Phys. Chem. Solids 67, 601-604 (2006). abstract on journal page
    2005
    • M. Poulsen, F. Jensen, O. Bunk, R. Feidenhans'l, and D.W. Breiby, Silicon waveguides produced by wafer bonding, Appl. Phys. Lett. 87, 261904 (2005). abstract on journal page
    • D.W. Breiby, F. Hansteen, W. Pisula, O. Bunk, U. Kolb, J.W. Andreasen, K. Müllen, and M.M. Nielsen, In situ studies of phase transitions in thin discotic films, J. Phys. Chem. B 109, 22319 (2005). abstract on journal page
    • O. Bunk, F. Pfeiffer, M. Stampanoni, B.D. Patterson, C. Schulze-Briese, and C. David, X-ray beam-position monitoring in the sub-micrometre and sub-second regime, J. Synchrotron Rad. 12, 795 (2005). abstract on journal page
    • D. W. Breiby, O. Bunk, W. Pisula, T.I. Sølling, A. Tracz, T. Pakula, K. Müllen, and M.M. Nielsen, Structure of zone-cast HBC-C12H25 films J. Am. Chem. Soc. 127, 11288 (2005). abstract on journal page
    • F. Pfeiffer, O. Bunk, C. Schulze-Briese, A. Diaz, T. Weitkamp, C. David, J.F. van der Veen, I. Vartanyants, and I. K. Robinson, Shearing interferometer for quantifying the coherence of hard x-ray beams, Phys. Rev. Lett. 94, 164801 (2005). abstract on journal page
    • C.M. Schlepütz, R. Herger, P.R. Willmott, B.D. Patterson, O. Bunk, C. Brönnimann, B. Henrich, G.Hülsen, and E.F. Eikenberry, Improved data acquisition in grazing-incidence x-ray scattering experiments using a pixel detector, Acta Cryst. A 61, 418 (2005). abstract on journal page
    • D.W. Breiby, T.I. Sølling, O. Bunk, R. Bøgelund Nyberg, K. Norrman, and M.M. Nielsen, Structural surprises in friction-deposited films of poly(tetrafluoroethylene), Macromolecules 38, 2383 (2005). abstract on journal page
    • J. Dalmas, H. Oughaddou, C. Léandri, J.-M. Gay, G. Le Lay, G. Tréglia, B. Aufray, O. Bunk, and R.L. Johnson, Ordered surface alloy formation of immiscible metals: The case of Pb deposited on Ag(111) Phys. Rev. B, 72, 155424 (2005). abstract on journal page
    2004
    • O. Bunk and M. M. Nielsen, Angle calculations for a z-axis / (2S+2D) hybrid diffractometer, J. Appl. Cryst. 37, 216 (2004). abstract on journal page
    • B.W. Laursen, K.Nørgaard, N. Reitzel, J.B. Simonsen, C.B. Nielsen, J. Als-Nielsen, T. Bjørnholm, T.I. Sølling, M.M. Nielsen, O. Bunk, K. Kjær, N. Tchebotareva, M.D. Watson, K. Müllen, and J. Piris, Macroscopic alignment of graphene stacks by Langmuir-Blodgett deposition of amphiphilic hexabenzocoronenes, Langmuir 20, 4139 (2004). abstract on journal page
    • C. Léandri, H. Oughaddou, J.M. Gay, B. Aufray, G. Le Lay, J.P. Bibérian, A. Ranguis, O. Bunk, and R.L. Johnson, Self-assembled germanium nano-clusters on silver(110), Surf. Sci. 573, L369 (2004). abstract on journal page
    2003
    • O. Bunk, M.M. Nielsen, T.I. Sølling, A.M. van de Craats, and N. Stutzmann, Induced alignment of a solution-cast discotic hexabenzocoronene derivative for electronic devices investigated by surface x-ray diffraction, J. Am. Chem. Soc. 125, 2252 (2003). abstract on journal page
    • A. M. van de Craats, N. Stutzmann, O. Bunk, M.M. Nielsen, M. Watson, K. Müllen, H.D. Chancy, H. Sirringhaus, and R.H. Friend, Meso-epitaxial solution-growth of self-organising discotic liquid-crystalline semiconductors, Adv. Mater. 15, 495 (2003). abstract on journal page
    • W. Weigand, A. Müller, L. Kilian, T. Schallenberg, P. Bach, G. Schmidt, L.W. Molenkamp, O. Bunk, R.L. Johnson, C. Kumpf, and E. Umbach, Structural investigation of the ZnSe(001)-c(2x2) surface, Phys. Rev. B 68, 241314(R) (2003). abstract on journal page
    • C. Kumpf, A. Müller, W. Weigand, E. Umbach, J. Wagner, V. Wagner, S. Gundel, L. Hansen, J. Geurts, O. Bunk, J.H. Zeysing, F. Wu, and R. L. Johnson, Analysis of structure and vibrational dynamics of the BeTe(001) surface using x-ray diffraction, Raman spectroscopy and density functional theory, Phys. Rev. B 68, 035339 (2003). abstract on journal page
    2002
    • G. Falkenberg, O. Bunk, R.L. Johnson, J.A. Rodriguez, and N. Takeuchi, Atomic structure of the indium-induced Ge(001)(nx4) surface reconstruction determined by scanning tunneling microscopy and ab initio calculations, Phys. Rev. B 66, 035305 (2002). abstract on journal page
    • M. Nielsen, M. Poulsen, O. Bunk, C. Kumpf, R. Feidenhans'l, R.L. Johnson, F. Jensen, and F. Grey, Mapping strain fields in ultrathin Si wafers by x-ray scattering, Appl. Phys. Lett. 80, 3412 (2002). abstract on journal page
    • S. Warren, A. Reitzle, A. Kazimirov, J.C. Ziegler, O. Bunk, L.X. Cao, F.U. Renner, D.M. Kolb, M.J. Bedzyk, and J. Zegenhagen, A structure study of the electroless deposition of Au on Si(111):H, Surf. Sci. 496, 287 (2002). abstract on journal page
    2001
    • O. Bunk, M.M. Nielsen, J.H. Zeysing, G. Falkenberg, F. Berg-Rasmussen, M. Nielsen, C. Kumpf, Y. Su, R. Feidenhans'l, and R.L. Johnson, Ge(001)-(2 1 0 3)-Pb (2 1 0 6)-Pb: low-temperature two-dimensional phase transition->, New J. Phys. 3, 13.1 (2001). abstract on journal page
    • C. Kumpf, D. Smilgies, E. Landemark, M. Nielsen, R. Feidenhans'l, O. Bunk, J.H. Zeysing, Y. Su, R.L. Johnson, L. Cao, J. Zegenhagen, B.O. Fimland, L.D. Marks, and D. Ellis, Structure of metal-rich (001) surfaces of III-V compund semiconductors, Phys. Rev. B 64, 075307 (2001). abstract on journal page
    • C. Kumpf, L.D. Marks, D. Ellis, D. Smilgies, E. Landemark, M. Nielsen, R. Feidenhans'l, J. Zegenhagen, O. Bunk, J.H. Zeysing, Y. Su, and R.L. Johnson, Subsurface dimerization in III-V semiconductor (001) surfaces, Phys. Rev. Lett. 86, 3586 (2001). abstract on journal page
    2000
    • C. Kumpf, O. Bunk, J.H. Zeysing, Y. Su, M. Nielsen, R.L. Johnson, R. Feidenhans'l, and K. Bechgaard, Low-temperature structure of indium quantum chains on silicon, Phys. Rev. Lett. 85, 4916 (2000). abstract on journal page
    • C. Kumpf, O. Bunk, J.H. Zeysing, M.M. Nielsen, M. Nielsen, R. L. Johnson, and R. Feidenhans'l, Structural study of the commensurate-incommensurate low-temperature phase transition of Pb on Si(111), Surf. Sci. 448, L213 (2000). abstract on journal page
    • E.M. Lauridsen, J. Baker, M. Nielsen, R. Feidenhans'l, G. Falkenberg, O. Bunk, J.H. Zeysing, and R.L. Johnson, Structure determination of the Si-(001)-(2x1)-H reconstruction by surface x-ray diffraction: Weakening of the dimer bond by the addition of hydrogen, Surf. Sci. 453, 18 (2000). abstract on journal page
    • J.C. Ziegler, A. Reitzle, O. Bunk, J. Zegenhagen, and D.M. Kolb, Metal deposition on n-Si(111):H electrodes, Electrochimica Acta 45, 4599 (2000). abstract on journal page
    • J.C. Ziegler, G. Scherb, O. Bunk, A. Kazimirov, L.X. Cao, D.M. Kolb, R.L. Johnson, and J. Zegenhagen, Pb deposition on n-Si(111):H electrodes: an in-situ X-ray study, Surf. Sci. 452, 150 (2000). abstract on journal page
    • D. Sentenac, A. Fera, R. Opitz, B.I. Ostrovskij, O. Bunk, and W.H. de Jeu, X-ray scattering from freely suspended smectic films: resolution and other effects, Physica B 283, 232 (2000). abstract on journal page
    • H. Oughaddou, J.-M. Gay, B. Aufray, L. Lapena, G. Le Lay, O. Bunk, G. Falkenberg, J. H. Zeysing, and R. L. Johnson, Ge tetramer structure of the p(2sqrt(2)x4sqrt(2))R45o surface reconstruction of Ge/Ag(001): A surface X-ray diffraction and STM study, Phys. Rev. B 61, 5692 (2000). abstract on journal page
    1999
    • O. Bunk, Bestimmung der Struktur komplexer Halbleiter-Oberflächenrekonstruktionen mit Röntgenbeugung, PhD thesis, University of Hamburg (1999). Full text from the University of Hamburg library page.
    • O. Bunk, G. Falkenberg, J.H. Zeysing, R.L. Johnson, M. Nielsen, and R. Feidenhans'l, Comment on 'Structural model for the Si(001)4x3-In surface phase', Phys. Rev. B 60, 13905 (1999). abstract on journal page
    • O. Bunk, J.H. Zeysing, G. Falkenberg, R.L. Johnson, M. Nielsen, M.M. Nielsen, and R. Feidenhans'l, Phase transitions in two dimensions: The case of Sn adsorbed on Ge(111) surfaces, Phys. Rev. Lett. 83, 2226 (1999). abstract on journal page
    • O. Bunk, G. Falkenberg, J.H. Zeysing, L. Lottermoser, R.L. Johnson, M. Nielsen, F. Berg-Rasmussen, J. Baker, and R. Feidenhans'l, Structure determination of the indium-induced Si(111)-(4x1) reconstruction by surface x-ray diffraction, Phys. Rev. B 59, 12228 (1999). abstract on journal page
    • O. Bunk, G. Falkenberg, J.H. Zeysing, L. Lottermoser, R.L. Johnson, M. Nielsen, F. Berg-Rasmussen, and R. Feidenhans'l, Structure determination of the indium-induced Ge(103)-(1x1) reconstruction by surface x-ray diffraction, Appl. Surf. Sci. 142, 88 (1999). abstract on journal page
    • G.A. Eckstein, S. Maupai, A.S. Dakkouri, M. Stratmann, M. Nielsen, M.M. Nielsen, R. Feidenhans'l, J.H. Zeysing, O. Bunk, and R.L. Johnson, Surface structure of Au3Cu(001), Phys. Rev. B 60, 8321 (1999). abstract on journal page
    1998
    • O. Bunk, G. Falkenberg, L. Seehofer, J.H. Zeysing, R.L. Johnson, M. Nielsen, R. Feidenhans'l, and E. Landemark, Structure determination of the indium induced Si(001)-(4x3) reconstruction by surface x-ray diffraction and scanning tunneling microscopy, Appl. Surf. Sci. 123/124, 104 (1998). abstract on journal page
    • L. Lottermoser, T. van Gemmeren, O. Bunk, R. L. Johnson, E. Landemark, D. Smilgies, M. Nielsen, and R. Feidenhans'l, Bismuth on GaSb(110): structural determination of the 1x1 and 1x2 phases by surface x-ray diffraction, Surf. Rev. Lett. 5, 1043 (1998). abstract on journal page
    • T. van Gemmeren, L. Lottermoser, G. Falkenberg, O. Bunk, R.L. Johnson, R. Feidenhans'l, and M. Nielsen, Growth morphology and structure of bismuth thin films on GaSb(110), Surf. Sci. 414, 254 (1998). abstract on journal page
    1997
    • L. Seehofer, O. Bunk, G. Falkenberg, L. Lottermoser, R. Feidenhans'l, E. Landemark, M. Nielsen, and R.L. Johnson, Atomic structure of a stable high-index Ge surface: Ge(103)-(4x1), Surf. Sci. 381, L614 (1997). abstract on journal page
    The focus of my research moved from condensed matter physics over soft matter towards biomedical and materials science imaging on different length scales using novel techniques. Recurrent themes are a strong interest in cross-disciplinary research, the use of X-ray techniques and the development and perfection of experimental methods. Currently I focus on the following fields:
    • SAXS imaging of biomedical samples: Development of the technique of fast raster scanning of samples while recording small-angle X-ray scattering data at high speed. Development of the data analysis algrorithms and software to treat the up to one million data frames per sample. Extension of the technique towards 3D. In collaboration with medical experts study of human tissue samples. Examples are femoral head and breast for osteoporosis and cancer research, rat brain for new structural insights in demyelination, teeth for remineralization of carious lesions.
    • Coherent diffractive imaging: Development of the technique towards high resolution imaging of biomedical and materials science samples in three dimensions. In collaboration application to systems like bone, cement, and polymers.
    For an overview of the projects addressed over the years I suggest having a look at the folllowing articles. The descriptions try to put the publications in my subjective view of the context and include a few citations to publications that I am not co-authoring. Full reviews or coverage of the available literature are beyond the scope of this web-page. Please feel free to suggest additions or corrections.

    Scanning small-angle X-ray scattering (SAXS)

    O. Bunk, M. Bech, T.H. Jensen, R. Feidenhans'l, T. Binderup, A. Menzel, and F. Pfeiffer, Multimodal x-ray scatter imaging, New J. Phys. 11, 123016 (2009). abstract and open-access PDF file on journal page


    Small-angle X-ray scattering (SAXS) in raster-scanning mode as imaging technique has been among the first experiments performed at the cSAXS beamline after it went into pilot operation mid 2007. We soon went to on-the-fly scans and got in several development steps the PILATUS 2M acquisition rate up to its maximum of about 30 Hz and the jitter to well below one point. The above cited paper describes the online analysis for these scanning SAXS data. Deviating from the procedure described there we typically record the transmission via the X-ray beamstop rather than performing separate scans with a 2D detector to retrieve phase contrast as well. Demonstrations of the technique are SAXS tomography on myelin in a rat brain [NeuroImage 57, 124-129 (2011) and Phys. Med. Biol. 56, 1717-1726 (2011)], the structure of mineralized collagen in bone [J. Appl. Cryst. 47, 1-8 (2014) and Sci. Rep. 2, 435 (2012)], teeth and the potential remineralization of carious leasions [Acta Biomater. 10, 355-364 (2014) and Biointerphases 7, 4 (2012)] as well as polymers [J. Mater. Res. 25, 1118-1130 (2010) and Chimia, 68 66-72 (2014)]. There is still a lot work to be done on the data analysis side. A first promising step has been the determination of the orientation of ultrastructure in 3D by analyzing scanning SAXS data of sample tilt-series' on a number of consecutive 2D slices [Bone 71, 42-52 (2015)]. Two non-destructive approaches for determining the orientation of ultrastructure in 3D have been published side-by-side [Nature 527, 349-352 (2015), Nature 527, 353-356 (2015)]. The extension to the full momentum-transfer range is computationally expensive. Further work in this field is hopefully triggered by these advances.

    Ptychographic coherent diffractive imaging

    P. Thibault, M. Dierolf, A. Menzel, O. Bunk, C. David, and F. Pfeiffer, High-Resolution Scanning X-ray Diffraction Microscopy, Science 321, 379-382 (2008). abstract on journal page


    The idea of circumventing the phase-problem by a scheme called ptychography dates back to Hoppe's suggestion in 1969, including the extension to non-periodic samples [Acta Cryst. A 25, 495 (1969), ibid, p. 508]. John Rodenburg's pioneering suggestion of combining ptychography with iterative phase retrieval schemes has been demonstrated together with him for X-rays at the Swiss Light Source [Phys. Rev. Lett. 98, 034801 (2007)]. The above cited paper combines instrumental improvements with the introduction of the difference map algorithm for refining both the probe and the sample. This improved the quality of the reconstructions of the exit wave of the sample considerably. It allowed as first application for the characterization of X-ray optics [Ultramicroscopy 110, 325-329 (2010) and Optics Express 18, 23420-23427 (2010)] at a resolution down to 8nm in 2D [Optics Express 19, 21333-21344 (2011)] and with the EIGER detector at a speed of 25'000 resolution elements per second [Optics Express, 22, 14859-14870 (2014)]. The step from 2D to 3D ptychographic imaging [Nature 467, 436-439 (2010)] initiated the step from pure method development towards first applications like imaging of cement pastes [Cem. Con. Comp. 36, 71-77 (2013), Langmuir 31, 3779-3783 (2015)], carbon fibers [ Carbon 67, 98-103 (2014)], paint New J. of Phys. 13, 103022 (2011)], catalyst particles [ChemCatChem 7, 413-416 (2015)], fossiles [Proc. R. Soc. B 282, 20151169 (2015)], and clay particles [Appl. Clay Science 118, 258–264 (2015)], and in situ studies of silk fiber hydration [Macromolecules 46, 434 (2013)] and a micro-composite under compression [Adv. Eng. Mater. (2015)]. Nevertheless, a number of projects has been performed in parallel on the method development side. This includes algorithmic developments like the automatic alignment of projections [Optics Express 19, 21345-21357 (2011)], validation of the quantitativeness of ptychographic imaging in 3D [Phys. Rev. B. 85, 020104(R) (2012)], investigation of the influence of the illumination function on the reconstruction [Phys. Rev. B. 86, 100103(R) (2012)], and the combination of coarse-scale STXM with tomographic ptychographic coherent diffraction imaging as interior tomography [Optica 2, 259-266 (2015)]. First cryo tomography on cellular ultrastructure [J. Struct. Biol. 192, 461-469 (2015), Addendum in J. Struct. Biol. 193, 83 (2016)] falls into both categories, first applications and method developments. On the instrumental side we started in 2010 the OMNY project. One of the key components is the error motion compensating tracking interferometer [Opt. Eng. 54, 054101 (2015)]. Already the test setup [Rev. Sci. Instrum. 83, 073703 (2012)] enabled imaging of a test sample at an isotropic resolution in 3D of 16 nm [Scientific Reports 4, 3857 (2014)], demonstrating with this 'world record' the achievements of the team on both instrumental and algorithmic aspects of ptychographic imaging. These developments have been recognized with the Innovation Award on Synchrotron Radiation of the year 2014.

    Confined fluids

    O. Bunk, A. Diaz, F. Pfeiffer, C. David, B. Schmitt, D.K. Satapathy, and J.F. van der Veen, Diffractive imaging for periodic samples: retrieving one-dimensional concentration profiles across microfluidic channels, Acta Cryst. A 63, 306-314 (2007). abstract on journal page


    Imaging the confinement-induced ordering of liquids as a function of the distance between the confining walls is feasible using for example X-rays [EPL 88, 36004 (2009), J. Phys Condens. Matter 22, 235102 (2010), J. Synchrotron Rad. 17 465-472 (2010) and EPL 99, 26001 (2012)]. To avoid the instrumental challenge of dynamically controlling the gap width one can use gratings of fixed gap width and period and combine gratings with different parameters on a single chip. The technique of producing high-aspect ratio gratings has been developed at PSI earlier [Microelectronic Engineering 841172-1177 (2007)] to use these for Talbot interferometry, see next point below. The aim of the data analysis is retrieving the density profile of the confined fluid across an average gap of such a grating. For this purpose the exit wave of the grating is retrieved from the diffraction intensities. The iterative phase-retrieval described in the above cited article has some similarity to crystallography since partially coherent radiation is used and support constraints that resemble solvent flattening, to give an example. Phase retrieval yields the exit wave that contains information on the density of the confined fluid but also effects like scattering from the confining walls. These effects can be minimized analyitically [Appl. Phys. Lett. 92, 214105 (2008), Optics Express 16, 20522-20529 (2008), and J. Appl. Cryst. 42, 1129-1138 (2009)].

    Grating interferometry

    F. Pfeiffer, T. Weitkamp, O. Bunk, and C. David, Phase retrieval and differential phase-contrast imaging with low-brilliance x-ray sources, Nature Phys. 2, 258 (2006). abstract on journal page


    Grating interferometry or Talbot interferometry has been used initially for phase-contrast imaging and metrology applications like the characterization of wave fronts at synchrotron radiation sources [Applied Physics Letters 86 (2005), 054101 and Phys. Rev. Lett. 94, 164801 (2005)]. The above cited publication describes the extension to lab-based sources of lower spatial coherence by using a source grating that creates an array of mutually incoherent but individually partially coherent sources. The images created by these sources overlap on the detector and create a phase-contrast image while still efficiently using a larger portion of the X-ray flux provided by the source. This three-grating variant of the technique has been extended to neutron sources [Phys. Rev. Lett. 96, 215505 (2006), Erratum, Phys. Rev. Lett. 97, 069905(E) (2006), and Rev. Sci. Instrum. 79, 053703 (2008)]. Apart from absorption and differential phase-contast, the Talbot interferometer provides a scattering-based so called dark-field or decoherence signal as well [Nature Materials 7, 134-137 (2008) and Phys. Rev. Lett. 101, 025504 (2008)]. The suitability of the technique for low brilliance sources like conventional X-ray tubes allows one to envision applications like mammography and so far the methodological progress and clinical results seem to be very promising [Investigative Radiology 46, 801 (2011), Nature Comm. 5, 3797 (2014), and Investigative Radiology 49, 131 (2014)].

    Thin organic films

    O. Bunk, M.M. Nielsen, T.I. Sølling, A.M. van de Craats, and N. Stutzmann, Induced alignment of a solution-cast discotic hexabenzocoronene derivative for electronic devices investigated by surface x-ray diffraction, J. Am. Chem. Soc. 125, 2252 (2003). abstract on journal page


    Friction-transferred poly(tetrafluoroethylene) (PTFE) has a number of interesting properties [Macromolecules 38, 2383 (2005)]. It can induce molecular and higher level alignment in thin films deposited in different ways [Adv. Mater. 15, 495 (2003), Langmuir 20, 4139 (2004)]. The above cited article describes the determination of the structure within three types of long-range ordered structures that are caused by the crystallisation of hexa(3,7-dimethyl-octanyl)hexa-peri-hexabenzocoronene (HBC-C8,2) on PTFE. The alignment of these three structures with the direction given by the macromolecules of the PTFE substrate influences the electronic properties of the thin film and thereby its potential for electronic applications. The existence of three aligned phases is also a possible explanation for the charge carrier mobility of this material being well below its intrinsic value. This pointed towards using different side chains or specialized deposition technqiues [J. Am. Chem. Soc. 127, 11288 (2005) and J. Phys. Chem. B 109, 22319 (2005)] to control the structure and thereby the properties of such thin organic films.

    Surface X-ray diffraction (SXRD)

    O. Bunk, G. Falkenberg, J.H. Zeysing, L. Lottermoser, R.L. Johnson, M. Nielsen, F. Berg-Rasmussen, J. Baker, and R. Feidenhans'l, Structure determination of the indium-induced Si(111)-(4x1) reconstruction by surface x-ray diffraction, Phys. Rev. B 59, 12228 (1999). abstract on journal page


    Solids interact through their surfaces with their environment which might rationalize why some material properties are greatly influenced by the surface or interface structure. Examples are heterogeneous catalysis or the Schottky barrier in metal-to-semiconductor contacts. In general, knowing the structure of surfaces is of interest in basic and applied sciences to achieve an understanding of structure property relationships for matter that is ordered in two dimensions. The determination of atomic structures has been an appealing application since the early days of X-ray investigations of matter both on powders and single crystals. With the advent of intense synchrotron radiation it became feasible to detect the relatively weak diffraction signal from the comparatively small amount of material at the surface of a sample. Specialized diffractometer geometries like six-axis or z-axis [J. Appl. Cryst. 37, 216 (2004)] can be used to keep in surface X-ray diffraction (SXRD) experiments the surface of a sample at constant grazing angle in the X-ray beam. Complex structures can be determined provided samples of high quality can be produced. Examples are the indium-induced Si(001)-(4x3) reconstruction [Appl. Surf. Sci. 123/124, 104 (1998) and Phys. Rev. B 60, 13905 (1999)] or the as well indium-induced Si(111)-(4x1) reconstruction which is described in the above cited paper. This structure has quasi 1D features which leads to interesting properties of the electronic structure. This surfaces undergoes a low temperature phase transition to a structure with (8x2) unit-cell, as determined by SXRD as well [Phys. Rev. Lett. 85, 4916 (2000)]. Other examples for low temperature phase transitions are Sn on Ge(111) [Phys. Rev. Lett. 83, 2226 (1999)], Pb on Si(111) [Surf. Sci. 448, L213 (2000)], and Pb on Ge(001) [New J. Phys. 3, 13.1 (2001)]. The last example, the phase transition of Pb on Ge(001) from a (2 1 0 3) to a (2 1 0 6) periodicity gives an example for how far one can push SXRD even at a 2nd generation synchrotron radiation source. The Pb atoms in a surface-monolayer exhibit a quasi-hexagonal arrangement, resembling Pb(111) termination of a crystal. Below this layer is the still dimerized Ge(001) surface, resembling the Ge(001)-(2x1) reconstruction. Anlysis of atomic displacement parameters reveals that some of the dimers are static and likely bond to the Pb layer, whereas others are either statically disordered or dynamically flipping at room temperature, as it is the case for the clean Ge(001)-(2x1) reconstruction. This variation is frozen in upon transition to the low temperature structure with twice the unit-cell size. The dynamic flipping of the dimers of the Ge(001)-(2x1) and Si(001)-(2x1) surfaces involves a charge transfer which can be used as qualitative exaplanation for the addition of hydrogen rendering the dimers symmetric and static [Surf. Sci. 453, 18 (2000)]. In all these studies careful sample prepration and pre-characterization as well as complementary scanning tunneling microscopy (STM) studies have been essential for determining the structure. Neither the local density of states at the surface, as imaged by STM, nor a model-based analysis of SXRD data without any prior information or boundary conditions will typically be able to determine a complex surface structure. Improved data collection using area detectors [Acta Cryst. A 61, 418 (2005)] and phase-retrieval techniques may provide a way out. X-ray techniques determine the average structure and can within certain limitations be used to determine several co-existing structures at once [Phys. Rev. B 60, 8321 (1999)]. For in-situ studies for example electrochemistry methods can be combined with SXRD [Surf. Sci. 452, 150 (2000), Electrochimica Acta 45, 4599 (2000), and Surf. Sci. 496, 287 (2002)]. Further details can be found in German in this thesis [Bestimmung der Struktur komplexer Halbleiter-Oberflächenrekonstruktionen mit Röntgenbeugung, PhD thesis, University of Hamburg (1999)].

    Member of the proposal review committee of the PETRA III facility at DESY (Germany) since 2014 and of MAX IV (Sweden) since 2017. Member of the scientific advisory committee (SAC) of the National Synchrotron Radiation Research Center (NSRRC, Taiwan) since 2015. In the past member of the SAC of Diamond Light Source (DLS, UK) 2013-2016, the SAC of the ALBA Synchrotron 2013-2014, the advisory committee of the Life Science and Biomedical technology Research center at NSLS-II (LSBR, USA) 2015-2016, review panel member for projects at BNL/NSLS II, DLS and NSRRC/TPS, reviewer for funding agencies and journals, member of search committees.