scholarly journals Ion Beam Microscopy: a Tool for Materials

2013 ◽  
Vol 19 (S4) ◽  
pp. 95-96
Author(s):  
L.C. Alves ◽  
V. Corregidor ◽  
T. Pinheiro ◽  
L. Ferreira
Keyword(s):  
Spatial Distribution ◽  
Spatial Resolution ◽  
Biological Samples ◽  
Mass Density ◽  
Ion Beam ◽  
Near Surface ◽  
X Ray ◽  
Beam Focusing ◽  
Combined Use ◽  
Pixe And Rbs

Ion Beam Analytical techniques (IBA) using MeV charged particles are powerful techniques for the study of different type of samples in several science fields such as Material Science, microelectronics or biology/biomedicine due to its fine sensitivity, versatility and “non-destructive” characteristics. The possibility of beam focusing and beam scanning adds spatial resolution down to the dm level and imaging capabilities then allowing the IBA techniques to become microscopy techniques.In the Nuclear Microprobe installed at IST/ITN several IBA techniques can be routinely used for materials characterization, the most common ones being PIXE (Particle Induced X-ray Emission), RBS (Rutherford Backscattering Spectrometry) and STIM (Scanning Transmission Ion Microscopy). Whether through their independent or combined use the most important thing of these techniques is the complementary information that they can grant. As any other X-ray spectroscopic technique pPIXE can also provide elemental identification (for Z>12) but further present their spatial distribution in the sample as well as, for thin biological samples (<20 <m), calculate their areal mass density. RBS on the other hand is able to probe sample in depth then allowing obtaining, for instance, elemental depth profile and at the same time sample matrix areal mass density. The combined use of PIXE and RBS then allows determining elemental concentration for thin biological samples. For the mentioned thin biological samples the ion beam energy loss when crossing them (base of the STIM technique), contains information on their density or thickness allowing unique information on its structure and morphology.Advantages and draw backs can always be taken into account when comparing with similar or competitive techniques. This is the case of PIXE and SEM-EDS which is quite unfavorable for PIXE in the case of image spatial resolution, but quite favorable if elemental sensitivity is considered. Due to the much lower X-ray spectrum background, detection limits for PIXE reach the tg/g level.As an example of application, some of the results obtained for PE-g-HEMA films are here shown. To allow their utilization as biomaterials for biomedical applications (e.g. drug delivery) apart from the needed mechanical properties and surface characteristics, biocompatibility of these materials is of fundamental importance. Regarding biocompatibility one important parameter to be assessed is its cytotoxicity that strongly depends on the contamination level at the surface. As shown in Fig. 1, MeV ion beam microscopy not only can provide major and trace element spatial distribution (combining PIXE and RBS data) but also valuable information on its near-surface structure (STIM). Furthermore, quantitative elemental analysis can be performed through the analysis of the PIXE spectra with sensitivity down to the rg/g level as also revealed in Figure 1.V. Corregidor acknowledges the funding support from the FCT-Ciência program.

scholarly journals Application of the Gatan X-ray Ultramicroscope (XuM) to the Investigation of Material and Biological Samples

2008 ◽  
Vol 16 (6) ◽  
pp. 14-17 ◽  
Author(s):  
Paul Mainwaring
Keyword(s):  
Sample Size ◽  
Spatial Resolution ◽  
Biological Samples ◽  
Easy Access ◽  
X Ray ◽  
Analytical Functions ◽  
Important Development ◽  
X Ray Imaging ◽  
Sem Imaging ◽  
Power Capability

X-ray ultramicroscopy in the SEM is a relatively new application in the wider field of X-ray microscopy. This latter field includes synchrotron and cabinet-based systems that vary in their X-ray power, capability, sample size, spatial resolution, and convenience. One important capability of the SEM-hosted X-ray microscope is that the normal SEM imaging and analytical functions such as secondary and backscattered imaging and microanalysis by EDX or WDS are unimpeded. X-ray imaging then serves as a complement to the normal use of the SEM. The convenience of easy access in an SEM lab to an X-ray microscope with 3D tomographic capability makes this an important development.

scholarly journals Artifacts from manganese reduction in rock samples prepared by focused ion beam (FIB) slicing for X-ray microspectroscopy

2019 ◽  
Vol 8 (1) ◽  
pp. 97-111
Author(s):  
Dorothea S. Macholdt ◽  
Jan-David Förster ◽  
Maren Müller ◽  
Bettina Weber ◽  
Michael Kappl ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Oxidation States ◽  
X Ray ◽  
Scientific Debate ◽  
Rock Samples ◽  
Valence States ◽  
Scanning Transmission ◽  
Visualization Techniques

Abstract. The spatial distribution of transition metal valence states is of broad interest in the microanalysis of geological and environmental samples. An example is rock varnish, a natural manganese (Mn)-rich rock coating, whose genesis mechanism remains a subject of scientific debate. We conducted scanning transmission X-ray microscopy with near-edge X-ray absorption fine-structure spectroscopy (STXM-NEXAFS) measurements of the abundance and spatial distribution of different Mn oxidation states within the nano- to micrometer thick varnish crusts. Such microanalytical measurements of thin and hard rock crusts require sample preparation with minimal contamination risk. Focused ion beam (FIB) slicing was used to obtain ∼100–1000 nm thin wedge-shaped slices of the samples for STXM, using standard parameters. However, while this preparation is suitable for investigating element distributions and structures in rock samples, we observed artifactual modifications of the Mn oxidation states at the surfaces of the FIB slices. Our results suggest that the preparation causes a reduction of Mn4+ to Mn2+. We draw attention to this issue, since FIB slicing, scanning electron microscopy (SEM) imaging, and other preparation and visualization techniques operating in the kilo-electron-volt range are well-established in geosciences, but researchers are often unaware of the potential for the reduction of Mn and possibly other elements in the samples.

Development of a Submilli-PIXE Camera

1998 ◽  
Vol 08 (02n03) ◽  
pp. 209-216 ◽  
Author(s):  
S. MATSUYAMA ◽  
K. GOTOH ◽  
K. ISHII ◽  
H. YAMAZAKI ◽  
T. SATOH ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Spatial Resolution ◽  
Data Acquisition System ◽  
Beam Line ◽  
Beam Position ◽  
Pixe Analysis ◽  
X Ray ◽  
System A ◽  
Line Beam ◽  
Analysis System

We developed a PIXE analysis system which provides spatial distribution images of elements in a region of several cm2 with a spatial resolution of < 0.5 mm. We call this system a submilli-PIXE camera. This system consists of a submilli-beam line, beam scanners and a data acquisition system in which the X-ray energy and the beam position are simultaneously measured. We demonstrate the usefulness of the submilli-PIXE camera by analyzing the surface of a shell and of granite.

ION BEAM LITHOGRAPHY AND NANOFABRICATION: A REVIEW

2005 ◽  
Vol 04 (03) ◽  
pp. 269-286 ◽  
Author(s):  
F. WATT ◽  
A. A. BETTIOL ◽  
J. A. VAN KAN ◽  
E. J. TEO ◽  
M. B. H. BREESE
Keyword(s):  
Mass Production ◽  
Large Scale ◽  
Focused Ion Beam ◽  
Extreme Ultraviolet ◽  
Ion Beam ◽  
Large Area ◽  
Near Surface ◽  
X Ray ◽  
Projection Lithography ◽  
New Generation

To overcome the diffraction constraints of traditional optical lithography, the next generation lithographies (NGLs) will utilize any one or more of EUV (extreme ultraviolet), X-ray, electron or ion beam technologies to produce sub-100 nm features. Perhaps the most under-developed and under-rated is the utilization of ions for lithographic purposes. All three ion beam techniques, FIB (Focused Ion Beam), Proton Beam Writing (p-beam writing) and Ion Projection Lithography (IPL) have now breached the technologically difficult 100 nm barrier, and are now capable of fabricating structures at the nanoscale. FIB, p-beam writing and IPL have the flexibility and potential to become leading contenders as NGLs. The three ion beam techniques have widely different attributes, and as such have their own strengths, niche areas and application areas. The physical principles underlying ion beam interactions with materials are described, together with a comparison with other lithographic techniques (electron beam writing and EUV/X-ray lithography). IPL follows the traditional lines of lithography, utilizing large area masks through which a pattern is replicated in resist material which can be used to modify the near-surface properties. In IPL, the complete absence of diffraction effects coupled with ability to tailor the depth of ion penetration to suit the resist thickness or the depth of modification are prime characteristics of this technique, as is the ability to pattern a large area in a single brief irradiation exposure without any wet processing steps. p-beam writing and FIB are direct write (maskless) processes, which for a long time have been considered too slow for mass production. However, these two techniques may have some distinct advantages when used in combination with nanoimprinting and pattern transfer. FIB can produce master stamps in any material, and p-beam writing is ideal for producing three-dimensional high-aspect ratio metallic stamps of precise geometry. The transfer of large scale patterns using nanoimprinting represents a technique of high potential for the mass production of a new generation of high area, high density, low dimensional structures. Finally a cross section of applications are chosen to demonstrate the potential of these new generation ion beam nanolithographies.

STEM/X-ray microanalysis across α/γ interfaces in Fe-Ni meteorites

1978 ◽  
Vol 36 (1) ◽  
pp. 416-417
Author(s):  
D. B. Williams ◽  
J. I. Goldstein
Keyword(s):  
Electron Beam ◽  
Spatial Resolution ◽  
Ion Beam ◽  
Finite Thickness ◽  
Theoretical Models ◽  
X Ray ◽  
Internal Precipitation ◽  
Precipitation Reactions ◽  
Two Phases ◽  
Characteristic Microstructure

Fe-Ni meteorites have cooled at rates ∼1-10°C/106 years giving rise to a characteristic microstructure of Widmanstatten bcc α plates that have nucleated and grown from the parent fcc γ phase. This transformation results in rejection of Ni into the remaining γ, which also exhibits a variety of internal precipitation reactions. The Ni concentration at the α/γ interface should be close to the equilibrium value between the two phases and this has been determined in several meteorites, using a Philips EM300 TEM/STEM equipped with X-ray microanalytical facilities. The sharp α/γ interface also permits a practical determination to be made of the spatial resolution of the technique. This has been performed and the result compared with the predictions of two theoretical models describing the spatial resolution in terms of the spreading of the electron beam within specimens of finite thickness.Specimens of the meteorites were sectioned such that the α/γ interface was normal to the surface, then 3mm discs were spark machined, ground to ∼100 μm thick, then ion beam thinned to electron transparency

Measurements of Thickness, Surface Roughness and Corrosion Performance of 1-10 nm Thick CNx Films

2003 ◽  
Author(s):  
Dejun Li ◽  
Yanfeng Chen ◽  
Yip-Wah Chung
Keyword(s):  
Surface Roughness ◽  
Rotation Speed ◽  
Unit Area ◽  
Mass Density ◽  
Ion Beam ◽  
X Ray ◽  
Pulsed Dc ◽  
Beam Analysis ◽  
Pulsed Dc Magnetron Sputtering ◽  
Cnx Films

Nitrogenated carbon (CNx) films were synthesized by using pulsed dc magnetron sputtering. When grown with substrate tilt of 45° and rotation speed of 20–25 rpm, the root-mean-square surface roughness is ∼0.3 nm when sampled over 20×20 μm2 areas, increasing to ∼0.4 nm when sampled over ∼0.05×3 cm2 using x-ray reflectivity measurements. X-ray reflectivity measurements showed that the mass density of these CNx films is ∼2.0 gm/cc, independent of film thickness from ∼1 to 10 nm, consistent with ion beam analysis. CNx films deposited with substrate tilt of 45° and rotation speed of 20–25 rpm have about 1/3 fewer corrosion spots per unit area than those without. Reducing CNx thickness from 3 to 1 nm results in marked increase in corrosion currents.

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