| 1. |
- Achilles, Silvio, et al.
(författare)
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GPU-Accelerated Coupled Ptychographic Tomography
- 2022
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Ingår i: Developments in X-Ray Tomography XIV. - : SPIE. - 1996-756X .- 0277-786X. - 9781510654686 ; 12242
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Konferensbidrag (refereegranskat)abstract
- Scanning coherent X-ray microscopy (ptychography) has gained considerable interest during the last decade since the performance of this indirect imaging technique does not necessarily rely on the quality of the X-ray optics and, in principle, can achieve highest spatial resolution in X-ray imaging. The method can be easily extended to 3D by adding standard tomographic reconstruction schemes. However, the tomographic reconstruction is often applied in a subsequent step using a sequence of aligned ptychographic 2D projections. In this contribution, we outline current developments of a GPU-accelerated framework for direct 3D ptychography, coupling 2D ptychography and tomography. The program utilizes a custom GPU-accelerated framework for ptychography that offers three distinct ptychographic reconstruction algorithms. The tomographic reconstruction runs simultaneously and uses numerical routines of the ASTRA Toolbox. This parallel-computing approach results in a high performance increase considerably reducing the reconstruction time of 3D ptychographic datasets.
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| 2. |
- Banerjee, Srutarshi, et al.
(författare)
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3D imaging of magnetic domains in Nd2Fe14B using scanning hard X-ray nanotomography
- 2024
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Ingår i: Journal of Synchrotron Radiation. - 0909-0495. ; 31:Pt 4, s. 877-887
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Tidskriftsartikel (refereegranskat)abstract
- Nanoscale structural and electronic heterogeneities are prevalent in condensed matter physics. Investigating these heterogeneities in 3D has become an important task for understanding material properties. To provide a tool to unravel the connection between nanoscale heterogeneity and macroscopic emergent properties in magnetic materials, scanning transmission X-ray microscopy (STXM) is combined with X-ray magnetic circular dichroism. A vector tomography algorithm has been developed to reconstruct the full 3D magnetic vector field without any prior noise assumptions or knowledge about the sample. Two tomographic scans around the vertical axis are acquired on single-crystalline Nd2Fe14B pillars tilted at two different angles, with 2D STXM projections recorded using a focused 120 nm X-ray beam with left and right circular polarization. Image alignment and iterative registration have been implemented based on the 2D STXM projections for the two tilts. Dichroic projections obtained from difference images are used for the tomographic reconstruction to obtain the 3D magnetization distribution at the nanoscale.
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| 3. |
- Björling, Alexander, et al.
(författare)
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Contrast - a lightweight Python framework for beamline orchestration and data acquisition
- 2021
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Ingår i: Journal of Synchrotron Radiation. - 1600-5775. ; 28:4, s. 1253-1260
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Tidskriftsartikel (refereegranskat)abstract
- The emergence of fourth-generation synchrotrons is prompting the development of new systems for experimental control and data acquisition. However, as general control systems are designed to cover a wide set of instruments and techniques, they tend to become large and complicated, at the cost of experimental flexibility. Here we present Contrast, a simple Python framework for interacting with beamline components, orchestrating experiments and managing data acquisition. The system is presented and demonstrated via its application at the NanoMAX beamline of the MAX IV Laboratory.
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| 4. |
- Björling, Alexander, et al.
(författare)
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Ptychographic characterization of a coherent nanofocused X-ray beam
- 2020
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Ingår i: Optics Express. - : OPTICAL SOC AMER. - 1094-4087. ; 28:4, s. 5069-5076
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Tidskriftsartikel (refereegranskat)abstract
- The NanoMAX hard X-ray nanoprobe is the first beamline to take full advantage of the diffraction-limited storage ring at the MAX IV synchrotron and delivers a high coherent photon flux for applications in diffraction and imaging. Here, we characterize its coherent and focused beam using ptychographic analysis. We derive beam profiles in the energy range 6-22 keV and estimate the coherent flux based on a probe mode decomposition approach.
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| 5. |
- Carbone, Dina, et al.
(författare)
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Design and performance of a dedicated coherent X-ray scanning diffraction instrument at beamline NanoMAX of MAX IV
- 2022
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Ingår i: Journal of Synchrotron Radiation. - 1600-5775. ; 29, s. 876-887
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Tidskriftsartikel (refereegranskat)abstract
- The diffraction endstation of the NanoMAX beamline is designed to provide high-flux coherent X-ray nano-beams for experiments requiring many degrees of freedom for sample and detector. The endstation is equipped with high-efficiency Kirkpatrick-Baez mirror focusing optics and a two-circle goniometer supporting a positioning and scanning device, designed to carry a compact sample environment. A robot is used as a detector arm. The endstation, in continued development, has been in user operation since summer 2017.
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| 6. |
- Johansson, Ulf, et al.
(författare)
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NanoMAX : the hard X-ray nanoprobe beamline at the MAX IV Laboratory
- 2021
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Ingår i: Journal of Synchrotron Radiation. - : International Union of Crystallography (IUCr). - 0909-0495 .- 1600-5775. ; 28, s. 1935-1947
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Tidskriftsartikel (refereegranskat)abstract
- NanoMAX is the first hard X-ray nanoprobe beamline at the MAX IV laboratory. It utilizes the unique properties of the world's first operational multi-bend achromat storage ring to provide an intense and coherent focused beam for experiments with several methods. In this paper we present the beamline optics design in detail, show the performance figures, and give an overview of the surrounding infrastructure and the operational diffraction endstation.
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| 7. |
- Kahnt, Maik
(författare)
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3D nano-tomography using coherent X-rays
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- X-rays allow to non-destructively investigate biological, chemical or physical processes at the nano-scale. Their high penetration depth in matter allows to investigate samples even inside sample environments, which would be difficult with complementary methods such as transmission electron microscopy (TEM). The microscopy technique ptychography has been established in X-ray imaging in recent years. Utilizing the short wavelengths of X-rays, resolutions of about 10 nm and below have been achieved in the reconstructed projection images. However, projections provide no information about the spatial distribution of features along the beam axis. Knowing the structure of materials and objects in three spatial dimensions is key to understanding their properties and function. Hence, two-dimensional ptychography has been extended to three spatial dimensions based on tomographic methods known from radiographs and computed tomography (CT) resulting in a method called ptychographic X-ray computed tomography (PXCT). Using PXCT quantitative three-dimensional maps of the complex index of refraction of the sample can be reconstructed, which yield quantitative information on the local electron density. Such PXCT measurements are very time intensive to perform, very computing intensive to reconstruct and are based on several limiting approximations. In this work, a detailed description of PXCT and its limitations is given. From that starting point, a coupled ptychographic tomography (CPT) algorithm, improving on the PXCT algorithm in terms of alignment and sampling requirements, is presented and tested on experimental data. Moreover, a resonant PXCT experiment is performed at the Ga-K absorption edge, allowing for additional elemental and chemical information inside the reconstructed volume. Afterwards, the shared limit of both the PXCT algorithm and the CPT algorithm, the thin-sample approximation, is addressed by presenting a multi-slice approach utilizing the propagation of the X-ray beam in the sample. In total three different experiments, performed at the hard X-ray nanoprobe endstation at beamline P06 at the PETRA III synchrotron radiation source, are presented in this work.
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| 8. |
- Kahnt, Maik, et al.
(författare)
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Complete alignment of a KB-mirror system guided by ptychography
- 2022
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Ingår i: Optics Express. - 1094-4087. ; 30:23, s. 42308-42322
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate how the individual mirrors of a high-quality Kirkpatrick-Baez (KB) mirror system can be aligned to each other to create an optimally focused beam, through minimizing aberrations in the phase of the ptychographically reconstructed pupil function. Different sources of misalignment and the distinctive phase artifacts they create are presented via experimental results from the alignment of the KB mirrors at the NanoMAX diffraction endstation. The catalog of aberration artifacts can be used to easily identify which parameter requires further tuning in the alignment of any KB mirror system.
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| 9. |
- Kahnt, Maik, et al.
(författare)
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Current capabilities of the imaging endstation at the NanoMAX beamline
- 2023
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Ingår i: AIP Conference Proceedings. - : AIP Publishing.
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Konferensbidrag (refereegranskat)abstract
- The new imaging endstation of the NanoMAX beamline is being designed to complement the already existing diffraction endstation: measurements with smaller beams at lower photons energies, with higher stability, in vacuum and with sample cooling at the measurement position, optimized for X-ray fluorescence mapping and ptychographic imaging in two and three spatial dimensions. This comes at the cost of reduced flexibility and fewer degrees of freedom. We hereby present the results of the in-air commissioning of the main components for the new endstation and the data quality that has already been achieved.
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| 10. |
- Kahnt, Maik, et al.
(författare)
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First ptychographic X-ray computed tomography experiment on the NanoMAX beamline
- 2020
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Ingår i: Journal of Applied Crystallography. - 0021-8898. ; 53, s. 1444-1451
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Tidskriftsartikel (refereegranskat)abstract
- Ptychographic X-ray computed tomography is a quantitative three-dimensional imaging technique offered to users of multiple synchrotron radiation sources. Its dependence on the coherent fraction of the available X-ray beam makes it perfectly suited to diffraction-limited storage rings. Although MAX IV is the first, and so far only, operating fourth-generation synchrotron light source, none of its experimental stations is currently set up to offer this technique to its users. The first ptychographic X-ray computed tomography experiment has therefore been performed on the NanoMAX beamline. From the results, information was gained about the current limitations of the experimental setup and where attention should be focused for improvement. The extracted parameters in terms of scanning speed, size of the imaged volume and achieved resolutions should provide a baseline for future users designing nano-Tomography experiments on the NanoMAX beamline.
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