Using a Polycapillary Optic as a Spatial Filter to Improve Micro Xray Analysis in Low-Vacuum and Environmental SEM Systems

2001 ◽  
Vol 7 (S2) ◽  
pp. 700-701
Author(s):  
Ning Gao ◽  
David Rohdeb
Keyword(s):  
Energy Dispersive Spectrometer ◽  
Spatial Filter ◽  
Image Contrast ◽  
Detection Sensitivity ◽  
X Rays ◽  
High Background ◽  
X Ray ◽  
Curved Channels ◽  
Probe Form ◽  
Environmental Sem

An inevitable consequence of the presence of the gas in the sample chamber of a low-vacuum scanning electron microscope (LV-SEM) and environmental SEM (ESEM) is the electron beam broadening due to the scattering in the gas. The electron broadening has a large impact on x-ray analysis because the fluorescent characteristic x rays generated far from the center of the electron probe form a high background, which reduces the detection sensitivity of x-ray analysis and degrades the x-ray image contrast. We report in this paper of using a polycapillary focusing x-ray optic between the sample and the energy-dispersive spectrometer as a spatial filter to filter out unwanted x-rays generated far from the specimen. As a result, the x-ray image contrast and the detection sensitivity of the system were notably improved.A polycapillary focusing optic collects a large solid angle of x rays from an x-ray source of small area at its input focus, guide them through the curved channels by multiple external total reflections, and focus them to the output focus.

High spatial resolution x-ray microanalysis of interfaces

1995 ◽  
Vol 53 ◽  
pp. 284-285
Author(s):  
J. R. Michael
Keyword(s):  
Spatial Resolution ◽  
Electron Probe ◽  
Solid Angle ◽  
Collection Efficiency ◽  
Spatial Scales ◽  
Energy Dispersive Spectrometer ◽  
X Rays ◽  
X Ray ◽  
Probe Size ◽  
Brightness Field

X-ray microanalysis in the analytical electron microscope (AEM) refers to a technique by which chemical composition can be determined on spatial scales of less than 10 nm. There are many factors that influence the quality of x-ray microanalysis. The minimum probe size with sufficient current for microanalysis that can be generated determines the ultimate spatial resolution of each individual microanalysis. However, it is also necessary to collect efficiently the x-rays generated. Modern high brightness field emission gun equipped AEMs can now generate probes that are less than 1 nm in diameter with high probe currents. Improving the x-ray collection solid angle of the solid state energy dispersive spectrometer (EDS) results in more efficient collection of x-ray generated by the interaction of the electron probe with the specimen, thus reducing the minimum detectability limit. The combination of decreased interaction volume due to smaller electron probe size and the increased collection efficiency due to larger solid angle of x-ray collection should enhance our ability to study interfacial segregation.

scholarly journals Erratum: X-Ray Optics on a Chip: Guiding X Rays in Curved Channels [Phys. Rev. Lett. 115 , 203902 (2015)]

2017 ◽  
Vol 118 (10) ◽  
Author(s):  
T. Salditt ◽  
S. Hoffmann ◽  
M. Vassholz ◽  
J. Haber ◽  
M. Osterhoff ◽  
...  
Keyword(s):  
X Rays ◽  
Ray Optics ◽  
X Ray ◽  
Curved Channels

scholarly journals Effect of Backscattered Radiation on X-Ray Image Contrast

2017 ◽  
Vol 9 (1) ◽  
pp. 105
Author(s):  
A. T. Naji ◽  
M. S. Jaafar ◽  
E. A. Ali ◽  
S. K. J. Al-Ani
Keyword(s):  
Radiation Exposure ◽  
Image Contrast ◽  
X Rays ◽  
Peak Voltage ◽  
X Ray ◽  
Geometrical Design ◽  
Remarkable Effect ◽  
Test Tool ◽  
Different Types

This paper assesses the effect of backscattered radiation on X-ray image contrast by evaluating the effect of backscatter reduction on X-ray image contrast. Contrast test tool RMI Densitometer, and different types of fabricated anti backscattered grids have been utilized in this study. The measurements are recorded at different exposure parameters such as X-ray tube peak voltage (kVp), and X-rays intensities (mAs). For each exposure, the contrast of the image is evaluated by measuring the variation in optical densities for aluminium steps wedge. The results showed that the x-ray image contrast can be enhanced by decreasing the amount of backscattered radiation, also the fabricated anti backscattered grids have a remarkable effect in the improvement of X-ray image contrast according to grid’s capability in reducing backscattered radiation. In addition, the effectiveness of fabricated grids in improving image contrast depends on the grid’s material and the geometrical design, as well as the radiation exposure parameters. The image contrast enhancements increased up to 36% with the use of crossed iron steel grid which placed under the film screen combination during exposure.

Quantitative analysis with a two-detector measuring system in in-air PIXE-design to improve detection sensitivity at low energies

2013 ◽  
Vol 23 (01n02) ◽  
pp. 55-67 ◽  
Author(s):  
K. Sera ◽  
S. Goto ◽  
C. Takahashi ◽  
Y. Saitoh
Keyword(s):  
Quantitative Analysis ◽  
Production Cross ◽  
Detection Sensitivity ◽  
Measuring System ◽  
X Rays ◽  
Standard Material ◽  
X Ray ◽  
New Device ◽  
Low Energies ◽  
Improve Detection Sensitivity

In this paper, a two-detector measuring system in in-air PIXE system composed of two Si(Li) detectors has been developed for simultaneous measurement of low- and high-Z elements. In order to improve detection sensitivity of the detector for low energy region, a new device which is attached at the tip of the detector has been designed. It is made of acryl and has a thin end on which a 1.5 μm-thick Mylar film is stuck. As a result, it exhibited a miraculous effect in improving detection sensitivity at low energies and it became possible to detect K X-rays of aluminium. In order to perform quantitative analysis in in-air system, we have measured detection efficiencies for the two Si(Li) detectors including the effect of X-ray absorption in air on the basis of the method that we developed. Concerning the beam energy at the target and corresponding X-ray production cross-sections, the same values as were reported in the previous paper were applicable since conditions of irradiating system were unchanged. It was confirmed that the new method allows us to quantitatively analyze all the elements heavier than aluminum and to obtain mostly the same results as those by in-vacuum PIXE for various kinds of samples. Accuracy of analysis was also confirmed by using a standard material.

scholarly journals Versatility of a hard X-ray Kirkpatrick–Baez focus characterized by ptychography

2013 ◽  
Vol 20 (3) ◽  
pp. 490-497 ◽  
Author(s):  
Klaus Giewekemeyer ◽  
Robin N. Wilke ◽  
Markus Osterhoff ◽  
Matthias Bartels ◽  
Sebastian Kalbfleisch ◽  
...  
Keyword(s):  
Spatial Filter ◽  
Large Field ◽  
X Rays ◽  
Height Profile ◽  
Diffractive Imaging ◽  
X Ray ◽  
The Past ◽  
Moderate Resolution ◽  
Nano Imaging

In the past decade Kirkpatrick–Baez (KB) mirrors have been established as powerful focusing systems in hard X-ray microscopy applications. Here a ptychographic characterization of the KB focus in the dedicated nano-imaging setup GINIX (Göttingen Instrument for Nano-Imaging with X-rays) at the P10 coherence beamline of the PETRA III synchrotron at HASLYLAB/DESY, Germany, is reported. More specifically, it is shown how aberrations in the KB beam, caused by imperfections in the height profile of the focusing mirrors, can be eliminated using a pinhole as a spatial filter near the focal plane. A combination of different pinhole sizes and illumination conditions of the KB setup makes the prepared optical setup well suited not only for high-resolution ptychographic coherent X-ray diffractive imaging but also for moderate-resolution/large-field-of-view propagation imaging in the divergent KB beam.

Tem and Stem Microanalysis

1976 ◽  
Vol 34 ◽  
pp. 562-563
Author(s):  
J. C. Russ
Keyword(s):  
Elemental Analysis ◽  
Energy Dispersive Spectrometer ◽  
Analytical Electron Microscopy ◽  
Energy Dispersive ◽  
X Rays ◽  
X Ray ◽  
Electron Probe Microanalyzer ◽  
Analytical Electron ◽  
High Resolution Images ◽  
Beam Currents

The technique widely know as “Analytical Electron Microscopy” is now being applied in a great variety of scientific and technical fields. It combines the examination of specimen morphology and structure with elemental analysis.The characteristic X-rays generated in the sample can be used to obtain elemental analysis of the region of the sample being hit by the electrons. The traditional electron probe microanalyzer used this method with wavelength-dispersive diffracting spectrometers . The advent of the SEM with its much lower electron beam currents (in order to achieve smaller beams for high resolution images) and rough samples (which do not lie on the focusing circle of a wavelength-dispersive spectrometer) nurtured the development of the energy-dispersive X-ray analyzer. The further use of this new method with the TEM and STEM has opened up entire new areas of application.As the name implies, the energy-dispersive spectrometer measures X-ray energy directly producing a spectrum of counts versus energy. The combination of higher geometrical and detector efficiency means that ED detectors can give count rates up to several hundred times greater than the WD spectrometer.

Influence of VPT Treatment on Microscopic Distribution of Trace Metal Contaminants and its Effect on TXRF Measurement

2018 ◽  
Vol 282 ◽  
pp. 309-313
Author(s):  
Rikiichi Ohno ◽  
Koichiro Saga
Keyword(s):  
Total Reflection ◽  
Detection Sensitivity ◽  
X Rays ◽  
Liquid Drops ◽  
X Ray ◽  
Condensed Form ◽  
Metal Atoms ◽  
Trace Metal Contaminants ◽  
Reflection Intensity ◽  
Microscopic Distribution

We have found that to the detection sensitivity of Total reflection X-ray fluorescent spectrometry (TXRF), the total volume of trace particles generated by vapor phase treatment (VPT) must be increased and metal atoms need to be included in the particles. The detection sensitivity for Cu is enhanced by assisting Cu ionization in the liquid drops condensed form the vapor. We consider that since incident and reflected X-rays resonate 30nm from the surface, the total reflection intensity of metals included in the particles is enhanced.

The Use of Collimating X-Ray Optics For Wavelength Dispersive Spectroscopy

1997 ◽  
Vol 3 (S2) ◽  
pp. 889-890 ◽  
Author(s):  
R. Agnello ◽  
J. Howard ◽  
J. McCarthy ◽  
D. OHara
Keyword(s):  
Point Source ◽  
Grazing Incidence ◽  
Detection Sensitivity ◽  
X Rays ◽  
Parallel Beam ◽  
Wavelength Dispersive Spectroscopy ◽  
X Ray ◽  
Glass Capillaries ◽  
Order Of Magnitude ◽  
Wavelength Dispersive Spectrometer

There has been much interest in the last few years in the technique for focusing x-rays into high intensity spots using tapered glass capillaries or other forms of grazing incident x-ray reflectors. The resulting microbeams have been used in applications that include microfluorescence, microdiffraction, tomography and lithography. Instead of focusing x-rays to a spot, a collimating optic can be used to capture x-rays from a point source and turn them into a collimated parallel beam at the exit aperture to the optic. Kirkland et. al. have pointed out that the use of such an optic could provide enhanced detection sensitivity in wavelength dispersive spectroscopy.We have developed a grazing incidence collimating x-ray optic that can be coupled to a simple wavelength dispersive spectrometer (WDS). This combined instrument was designed to enhance the intensity of x-rays from a sample by an order of magnitude or more in the energy range of 0 to 1 keV compared to a conventional WDS.

Elemental Analysis of thin Films Using Inner Shell Electron Energy Losses

1976 ◽  
Vol 34 ◽  
pp. 414-415
Author(s):  
D. E. Johnson ◽  
M. Isaacson
Keyword(s):  
Thin Films ◽  
Energy Loss ◽  
Electron Energy ◽  
Elemental Analysis ◽  
Large Fraction ◽  
Fluorescence Yield ◽  
Detection Sensitivity ◽  
X Rays ◽  
X Ray ◽  
Electron Energy Loss

The use of electron energy loss spectroscopy (ELS) for elemental analysis of thin films holds considerable promise. This technique has definite advantages in comparison with energy dispersive X-ray spectroscopy (EDS) for two fundamental reasons. First, the detection sensitivity is independent of the fluorescence yield, since for each inner shell excitation an energy loss electron exists as opposed to only a finite probability that an excitation will result in a X-ray emitted. Second, the information carrying energy loss electrons are contained in a small solid angle about 0° scattering angle as opposed to the resulting X-rays which are emitted uniformly over 4Π steradians. This means that a large fraction of the energy loss electrons can be detected (up to ∼90%) compared to only a small fraction (∼1%) of the emitted X-rays with an EDS system.

Application of X-Ray Optics to Energy Dispersive Spectroscopy

1998 ◽  
Vol 4 (S2) ◽  
pp. 178-179
Author(s):  
J. J. McCarthy ◽  
D. J. McMillan
Keyword(s):  
Energy Dispersive Spectroscopy ◽  
High Intensity ◽  
Grazing Incidence ◽  
Detection Sensitivity ◽  
X Rays ◽  
Wavelength Dispersive Spectroscopy ◽  
Ray Optics ◽  
X Ray ◽  
Capillary Optics ◽  
Convergent Beam

The application of x-ray optics for focusing x-rays into high intensity spots or for collimation of x-ray beams has been reported by several authors. Example applications for x-ray optics include microfluorescence, microdiffraction, tomography and lithography, and WDS. Kirkland et al. pointed out that the use of an optic, in a collimating configuration could provide enhanced detection sensitivity in wavelength dispersive spectroscopy. In these proceedings last year, Agnello et al. presented data from a new WDS device specifically designed to use a grazing incidence collimating x-ray optic that confirmed and extended the work of Kirkland.A few studies have appeared reporting the use X-ray optics in applications using EDS. Focusing x-ray optics have been used on both the excitation and detection side of EDS systems. In a series of papers, Carpenter and his collaborators describe an x-ray microprobe which uses capillary optics to provide an intense convergent beam of x-rays from a microfocus x-ray tube to excite the sample for x-ray microfluorescence studies. Wollman et al.

Sign in / Sign up

Export Citation Format

Share Document