Ultramicroscopy最新文献

{"title":"Phase offset method of ptychographic contrast reversal correction","authors":"Christoph Hofer,&nbsp;Chuang Gao,&nbsp;Tamazouzt Chennit,&nbsp;Biao Yuan,&nbsp;Timothy J. Pennycook","doi":"10.1016/j.ultramic.2024.113922","DOIUrl":"10.1016/j.ultramic.2024.113922","url":null,"abstract":"<div><p>The contrast transfer function of direct ptychography methods such as the single side band (SSB) method are single signed, yet these methods still sometimes exhibit contrast reversals, most often where the projected potentials are strong. In thicker samples central focusing often provides the best ptychographic contrast as this leads to defocus variations within the sample canceling out. However focusing away from the entrance surface is often undesirable as this degrades the annular dark field (ADF) signal. Here we discuss how phase wrap asymptotes in the frequency response of SSB ptychography give rise to contrast reversals, without the need for dynamical scattering, and how these can be counteracted by manipulating the phases such that the asymptotes are either shifted to higher frequencies or damped via amplitude modulation. This is what enables post collection defocus correction of contrast reversals. However, the phase offset method of counteracting contrast reversals we introduce here is generally found to be superior to post collection application of defocus, with greater reliability and generally stronger contrast. Importantly, the phase offset method also works for thin and thick samples where central focusing does not. Finally, the independence of the method from focus is useful for optical sectioning involving ptychography, improving interpretability by better disentangling the effects of strong potentials and focus.</p></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"258 ","pages":"Article 113922"},"PeriodicalIF":2.2,"publicationDate":"2024-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0304399124000019/pdfft?md5=252f4115db9a421645fc1ecee48bc6fc&pid=1-s2.0-S0304399124000019-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139397689","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Recovery of spatial frequencies in coherent diffraction imaging in the presence of a central obscuration","authors":"Atoosa Dejkameh ,&nbsp;Ricarda Nebling ,&nbsp;Uldis Locans ,&nbsp;Hyun-Su Kim ,&nbsp;Iacopo Mochi ,&nbsp;Yasin Ekinci","doi":"10.1016/j.ultramic.2023.113912","DOIUrl":"10.1016/j.ultramic.2023.113912","url":null,"abstract":"<div><p>Coherent diffraction imaging (CDI) and its scanning version, ptychography, are lensless imaging approaches used to iteratively retrieve a sample’s complex scattering amplitude from its measured diffraction patterns. These imaging methods are most useful in extreme ultraviolet (EUV) and X-ray regions of the electromagnetic spectrum, where efficient imaging optics are difficult to manufacture. CDI relies on high signal-to-noise ratio diffraction data to recover the phase, but increasing the flux can cause saturation effects on the detector. A conventional solution to this problem is to place a beam stop in front of the detector. The pixel masking method is a common solution to the problem of missing frequencies due to a beam stop. This paper describes the information redundancy in the recorded data set and expands on how the reconstruction algorithm can exploit this redundancy to estimate the missing frequencies. Thereafter, we modify the size of the beam stop in experimental and simulation data to assess the impact of the missing frequencies, investigate the extent to which the lost portion of the diffraction spectrum can be recovered, and quantify the effect of the beam stop on the image quality. The experimental findings and simulations conducted for EUV imaging demonstrate that when using a beam stop, the numerical aperture of the condenser is a crucial factor in the recovery of lost frequencies. Our thorough investigation of the reconstructed images provides information on the overall quality of reconstruction and highlights the vulnerable frequencies if the beam stop size is larger than the extent of the illumination NA. The outcome of this study can be applied to other sources of frequency loss, and it will contribute to the improvement of experiments and reconstruction algorithms in CDI.</p></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"258 ","pages":"Article 113912"},"PeriodicalIF":2.2,"publicationDate":"2023-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0304399123002292/pdfft?md5=0efa39d677d72d406052ce188a5a96ca&pid=1-s2.0-S0304399123002292-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139065160","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Point field emission electron source with a magnetically focused electron beam","authors":"Paweł Urbański, Piotr Szyszka, Marcin Białas, Tomasz Grzebyk","doi":"10.1016/j.ultramic.2023.113911","DOIUrl":"https://doi.org/10.1016/j.ultramic.2023.113911","url":null,"abstract":"<p>This paper presents a field emitter in the form of a silicon tip covered with a layer of carbon nanotubes. The emitted beam is focused with a set of two electrostatic lenses and – which is novelty in such structures – with a magnetic field. The presented approach gave very promising results. The field emitter was able to provide a high emission current (about 50 µA) and a beam with a small and homogeneous spot. Such electron sources are necessary components of many miniature MEMS and nanoelectronics devices. The presented source is dedicated especially for the use in currently developed MEMS X-ray sources and MEMS electron microscopes.</p>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"17 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139031305","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Point field emission electron source with a magnetically focused electron beam","authors":"Paweł Urbański,&nbsp;Piotr Szyszka,&nbsp;Marcin Białas,&nbsp;Tomasz Grzebyk","doi":"10.1016/j.ultramic.2023.113911","DOIUrl":"10.1016/j.ultramic.2023.113911","url":null,"abstract":"<div><p>This paper presents a field emitter in the form of a silicon tip covered with a layer of carbon nanotubes. The emitted beam is focused with a set of two electrostatic lenses and – which is novelty in such structures – with a magnetic field. The presented approach gave very promising results. The field emitter was able to provide a high emission current (about 50 µA) and a beam with a small and homogeneous spot. Such electron sources are necessary components of many miniature MEMS and nanoelectronics devices. The presented source is dedicated especially for the use in currently developed MEMS X-ray sources and MEMS electron microscopes.</p></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"258 ","pages":"Article 113911"},"PeriodicalIF":2.2,"publicationDate":"2023-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139024565","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Generational assessment of EBSD detectors for cross-correlation-based analysis: From scintillators to direct detection","authors":"Josephine DeRonja ,&nbsp;Matthew Nowell ,&nbsp;Stuart Wright ,&nbsp;Josh Kacher","doi":"10.1016/j.ultramic.2023.113913","DOIUrl":"10.1016/j.ultramic.2023.113913","url":null,"abstract":"<div><p>Introduced over ten years ago, cross-correlation-based electron backscatter diffraction has enabled high precision measurements of crystallographic rotations and elastic strain gradients at high spatial resolution. Since that time, there have been remarkable improvements in electron detector technology, including the advent of ultra-high speed detectors and the commercialization of direct detectors. In this study, we assess the efficacy of multiple generations of electron detectors for cross-correlation-based analysis using a single crystal Si sample as a reference. We show that, while improvements in precision are modest, there have been significant gains in the rate at which high-quality diffraction patterns can be collected. This has important implications in the size of datasets that can be collected and reduces the impact of drift and sample contamination.</p></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"257 ","pages":"Article 113913"},"PeriodicalIF":2.2,"publicationDate":"2023-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139031252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Does the order of elastic and inelastic scattering affect an image or is there a top bottom effect from inelastic scattering?","authors":"Peter Rez","doi":"10.1016/j.ultramic.2023.113890","DOIUrl":"10.1016/j.ultramic.2023.113890","url":null,"abstract":"<div><p>Especially for light elements inelastic scattering is more probable than the elastic scattering that conveys the structural information. The question arises as to whether an image using inelastically scattered electrons is different depending on whether the elastic or inelastic scattering happens first, is there a top-bottom effect. We show that since inelastic scattering is concentrated in a narrow range of angles, much less than typical Bragg angles in light element materials, the inelastic and elastic processes are separable and, to a very good approximation, there is no top-bottom effect. For weakly scattering thin biological specimens that are phase objects the separation is exact and there can be no top-bottom effect.</p></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"257 ","pages":"Article 113890"},"PeriodicalIF":2.2,"publicationDate":"2023-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138693087","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Correlative atomic force microscopy and scanning electron microscopy of bacteria-diamond-metal nanocomposites","authors":"David Rutherford ,&nbsp;Kateřina Kolářová ,&nbsp;Jaroslav Čech ,&nbsp;Petr Haušild ,&nbsp;Jaroslav Kuliček ,&nbsp;Egor Ukraintsev ,&nbsp;Štěpán Stehlík ,&nbsp;Radek Dao ,&nbsp;Jan Neuman ,&nbsp;Bohuslav Rezek","doi":"10.1016/j.ultramic.2023.113909","DOIUrl":"10.1016/j.ultramic.2023.113909","url":null,"abstract":"<div><p>Research investigating the interface between biological organisms and nanomaterials nowadays requires multi-faceted microscopic methods to elucidate the interaction mechanisms and effects. Here we describe a novel approach and methodology correlating data from an atomic force microscope inside a scanning electron microscope (AFM-in-SEM). This approach is demonstrated on bacteria-diamond-metal nanocomposite samples relevant in current life science research. We describe a procedure for preparing such multi-component test samples containing <em>E. coli</em> bacteria and chitosan-coated hydrogenated nanodiamonds decorated with silver nanoparticles on a carbon-coated gold grid. Microscopic topography information (AFM) is combined with chemical, material, and morphological information (SEM using SE and BSE at varied acceleration voltages) from the same region of interest and processed to create 3D correlative probe-electron microscopy (CPEM) images. We also establish a novel 3D RGB color image algorithm for merging multiple SE/BSE data from SEM with the AFM surface topography data which provides additional information about microscopic interaction of the diamond-metal nanocomposite with bacteria, not achievable by individual analyses. The methodology of CPEM data interpretation is independently corroborated by further <em>in-situ</em> (EDS) and <em>ex-situ</em> (micro-Raman) chemical characterization as well as by force volume AFM analysis. We also discuss the broader applicability and benefits of the methodology for life science research.</p></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"258 ","pages":"Article 113909"},"PeriodicalIF":2.2,"publicationDate":"2023-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138631652","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design and optimization of a conical electrostatic objective lens of a low-voltage scanning electron microscope for surface imaging and analysis in ultra-high-vacuum environment","authors":"Jeong-Woong Lee ,&nbsp;In-Yong Park ,&nbsp;Takashi Ogawa","doi":"10.1016/j.ultramic.2023.113908","DOIUrl":"10.1016/j.ultramic.2023.113908","url":null,"abstract":"<div><p>Low-voltage scanning electron microscopy (LV-SEM) with landing energies below 5 keV has been widely used due to its advantages in mitigating the damage and charging effects to a specimen and enhancing surface information due to small interaction volume of electrons inside a specimen. Additionally, for elemental analysis of the surfaces of bulk specimens with Auger electron spectroscopy (AES) or electron energy loss spectroscopy (EELS), ultra-high-vacuum (UHV) environment is essential to maintain clean surfaces without the absorption of gas molecules during the electron beam irradiation for the acquisition of spectral data. In this study, we propose the optimal design and condition of a conical Electrostatic Objective Lens (EOL) for a UHV LV-SEM to achieve the high spatial resolution and secondary electron (SE) detection efficiency. The EOL is composed of only the three electrodes (retarding, focusing and booster electrodes) and the insulators, which is suitable for maintaining a UHV environment with less out-gassing. The cone angle of the EOL is determined as 60° to integrate a spectrometer in the UHV LV-SEM and in a large size and a higher tilt angle of the sample. Through the optimization with the simulations, the EOL achieves the minimized spherical and chromatic aberration coefficients of 0.05 and 0.03 mm at the sample side, respectively, at the landing energy of 50 eV and the shortest working distance (WD) of 1 mm for high-resolution imaging. In addition, the probe diameter of the optimized EOL is 2.3 nm at 1 keV and 5.7 nm at 50 eV with a WD of 1 mm and a probe current of 10 pA, which are comparable to previously studied compound objective lenses with magnetic and electrostatic lenses. Using a longer WD of 4 mm for analysis, the probe diameter was 5.4 nm at 1 keV and the SE detection efficiency was 83.3 % owing to the separated scintillator detector structure from the booster electrode.</p><p>These results imply that the optimized EOL has the potential to be applied to a high-performance UHV LV-SEM for the surface imaging and analysis with a simple system configuration.</p></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"257 ","pages":"Article 113908"},"PeriodicalIF":2.2,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0304399123002255/pdfft?md5=ee2a1dfc31900e3dae27b5f667d8081b&pid=1-s2.0-S0304399123002255-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138632033","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Programmable comprehensive controller for multi-color 3D confocal spinning-disk image scanning microscope","authors":"Eli Flaxer ,&nbsp;Lanna Bram ,&nbsp;Alona Flaxer ,&nbsp;Yael Roichman ,&nbsp;Yuval Ebenstein","doi":"10.1016/j.ultramic.2023.113888","DOIUrl":"10.1016/j.ultramic.2023.113888","url":null,"abstract":"<div><p>This paper introduces a compact, portable, and highly accurate triggering control system for a 3D confocal spinning-disk image scanning microscope (CSD-ISM). Building upon on our previously published research, we expanded the hardware of the controller and synchronized it with a sub-micron translator which scans the object in the z-direction. As well as expanding the hardware, the software also was extended from previously published work similarly as it is stated for hardware while allowing full control over the 3D movement. We showed a clear and smooth 3D image made up of a collection of 2D images at different heights.</p></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"257 ","pages":"Article 113888"},"PeriodicalIF":2.2,"publicationDate":"2023-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138563933","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The target region focused imaging method for scanning ion conductance microscopy","authors":"Shengbo Gu ,&nbsp;Jian Zhuang ,&nbsp;Tianying Wang ,&nbsp;Shiting Hu ,&nbsp;Weilun Song ,&nbsp;Xiaobo Liao","doi":"10.1016/j.ultramic.2023.113910","DOIUrl":"10.1016/j.ultramic.2023.113910","url":null,"abstract":"<div><p>Scanning ion conductance microscopy (SICM) has developed rapidly and has wide applications in biomedicine, single-cell science and other fields. SICM scanning speed is limited by the conventional raster-type scanning method, which spends most of time on imaging the substrate and does not focus enough on the target area. In order to solve this problem, a target region focused (TRF) method is proposed, which can effectively avoid the scanning of unnecessary substrate areas and enables SICM to image the target area only to achieve high-speed and effective local scanning. TRF method and conventional hopping mode scanning method are compared in the experiments using breast cancer cells and rat basophilic leukemia cells as experimental materials. It was demonstrated that our method can reduce the scanning time for a single sample image significantly without losing scanning information or compromising the quality of imaging. The TRF method developed in this paper can provide an efficient and fast scanning strategy for improving the imaging performance of SICM systems, which can be applied to the dynamic features of cell samples in the fields of biology and pharmacology analysis.</p></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"257 ","pages":"Article 113910"},"PeriodicalIF":2.2,"publicationDate":"2023-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138563822","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}