Capillary Lens Research Articles

Focusing of x-rays emitted by a pyroelectric x-ray generator for micro x-ray fluorescence

Micro x-ray fluorescence spectroscopy (μXRF) is a technique for local chemical analyses of materials. There are several advantages in comparison to other similar methods like energy dispersive x-ray spectroscopy in a scanning electron microscope (SEM). The main advantage is the possible abdication of an evacuated sample chamber, which offers the possibility to analyze wet and oil contaminated specimens as well as specimens with intrinsic pores in addition to conventional samples used in SEM analyses. The subject of this report is the investigation of the pyroelectric effect with regard to its application for the generation of focused x-rays and first steps to a successive usage of the generated radiation for μXRF applications. In order to answer questions concerning the energy and intensity of primary radiation and geometric parameters for a successful focusing, this paper describes several experiments and results against the background of the described aims. Different setups and measurements have been used, optimizing the experimental setups to find the basic parameters to potentially generate focal spots of the primary x-rays. Emission behavior of electrons has been visualized and characterized by using a phosphor screen positioned in front of a pyroelectric crystal. Radiation has been measured and characterized by using an energy dispersive silicon drift x-ray detector. All x-ray experiments were executed in a vacuum test rig. This allowed the optimization of the working pressure of the residual gas surrounding the crystal in an evacuated atmosphere (rarefied air). It has been shown that emitted x-ray energies are strongly influenced by the vacuum pressure. Lithiumniobate and lithiumtantalate of different geometries were used as the pyroelectric material. Different target materials and target angles have been compared to optimize the combination of the constructed x-rays source with an aperture as well as with an x-ray optic to focus the primary x-rays. A glass fiber capillary lens was used as the focusing optic. A first step to a μXRF application is shown.

Liquid chromatography-tandem mass spectrometry determination of the degradation products of V-type nerve agnents, N,N-dialkylaminoethanesulfonic acids

Degradation products of V-type nerve agents are important markers of these toxic chemical warfare agents, hence their detection and identification is of high importance from verification point of view of Chemical Weapons Convention (CWC). We focused on detailed investigation of fragmentation of N, N-dialkylaminoethanesulfonic acids, degradation products of V-type nerve agents using liquid chromatography-tandem mass spectrometry (LC−MS/MS), a LCQ Deca XP max ion trap mass spectrometer via an electrospray ionization in ESI mode. Capillary and tube lens voltages were optimized to give maximum response to m/z 210 [M + H]+ ion of N,N-diisopropylaminoethanesulfonic acid. The main fragmentation pathways are loss of alkyl groups attached to the nitrogen atoms. Within the aims of CWC, LC−ESI-MSn represents an important tool to control the production of prohibited compounds among others due to a possibility of easy monitoring of their content in environmental matrices. The knowledge of the fragmentation pathway will be useful for the unambiguous identification of degradation products of V-type nerve agents in human urine matrices as well as environmental matrices in the Organization for the Prohibition of Chemical Weapons proficiency test.

毛细管X光透镜在塑料物证溯源中的应用

毛细管X光透镜在塑料物证溯源中的应用

毛细管X光会聚透镜在潜指纹提取中的应用

毛细管X光会聚透镜在潜指纹提取中的应用

毛细管X光会聚透镜在潜指纹提取中的应用

毛细管X光会聚透镜在潜指纹提取中的应用

毛细管X光会聚透镜在潜指纹提取中的应用

毛细管X光会聚透镜在潜指纹提取中的应用

X-ray micro-imaging by capillary optics

In this work the results on X-ray micro-imaging by means of novel polycapillary optical elements will be presented. To simulate various radiation propagation processes in both single capillary and polycapillary systems, a PolyCAD code was developed. The new experimental results on radiation redistribution by novel capillary lenses in comparison with simulated data will be reported. The images of characterized extended samples (~ 3 mm) were recorded with 6 μm resolution, the maximum provided by CCD. Polycapillary Optics CAD software X-ray tracing Imaging Confocal 02.60.Cb 02.70.-c 41.50. + h 42.15.-i 42.15.Dp 42.30.-d.

Experimental evaluation of X‐ray optics applied for microanalysis

AbstractThe performance of x‐ray capillary lenses has been evaluated. The tests were carried out using an x‐ray tube set‐up. A single glass capillary with tapered inner channel, a monolithic glass polycapillary, and an in‐house manufactured single metallic capillary with parabolic inner channel were characterized in terms of gain, spatial resolution, and element detection limits. The spatial resolution of a confocal set‐up utilizing a monolithic glass polycapillary and a polycapillary conical collimator has also been measured. The highest gain of about 2500 was observed for the glass polycapillary. The maximum gain achieved with the single glass capillary was equal to about 25, and the gain of the metallic capillary was only slightly greater than 1. For the glass capillary and polycapillary lenses, significant filtering of the higher‐energy photons (energy > 8 keV) was observed. The lowest relative detection limits were obtained with an ordinary cylindrical collimator and the polycapillary lens. Similar absolute detection limits were achieved with the use of the polycapillary and single capillary lenses. A relation between the ratios of the detection limits of elements achieved with different x‐ray lenses and the lens parameters (spatial resolution and gain) has been proposed and was verified experimentally. The monolithic polycapillary lens was found to be an optimum focusing device for an x‐ray tube‐based scanning spectrometer. This type of x‐ray lens can be coupled with a polycapillary conical collimator or a polycapillary half‐lens to make a confocal x‐ray microscope capable of depth profiling with a spatial resolution equal to about 30 micrometers. Copyright © 2008 John Wiley & Sons, Ltd.

整体毛细管X光透镜在大气颗粒物单颗粒分析中的应用

整体毛细管X光透镜在大气颗粒物单颗粒分析中的应用

Specific features of X-ray fluorescence analysis techniques using capillary lenses and synchrotron radiation

This paper discusses the features of an application of two versions of X-ray fluorescence analysis (XRF), commonly used at present, namely XRF using synchrotron radiation to excite the fluorescence in the sample investigated (SRXRF), and XRF using capillary X-ray optics. The operational characteristics of different models of micro-XRF spectrometers are considered. The general differences between conventional XRF and SRXRF and their influence on the choice of the analytical procedure are also presented. Examples of the typical errors resulting from the use of some classical analytical procedures in several applications are illustrated.

Convergent-beam diffraction of ultra-short hard X-ray pulses focused by a capillary lens

We report the generation of diffraction patterns using X-ray pulses from a fs-laser plasma focused by an X-ray capillary lens to a spot size smaller than 100 μm. A thin moving iron tape is irradiated at 10 Hz with 200 mJ/130 fs titanium–sapphire laser pulses. [Fe]Kα (λ=0.194 nm) radiation emitted from the rear side of the tape is focused to a spot by the capillary lens resulting in an intensity enhancement of about 1600. The ability of this system to effectively allow diffraction from samples of micron size is demonstrated by producing well-illuminated diffractograms from a Si(111) crystal with good signal to noise ratio obtained in only about 10 s. The different path lengths of propagation in the lens induce an angle-encoded delay of the converging X-ray pulse and thus provide the possibility of realizing a novel ultra-fast streak camera.

Semiempirical approach for standardless calibration in µ‐XRF spectrometry using capillary lenses

AbstractQuantitative µ‐XRF analysis based on standardless calibration is limited by the lack of information on the shape of the excitation spectrum resulting from using capillary lenses. The measurement of radiation scattered from a sample was used in combination with Monte Carlo simulation of radiation transport to estimate the energy spectral distribution of the excitation radiation. Further, a standardless calibration based on the fundamental parameter method implemented in the IAEA‐QXAS software package was carried out and verified for glass and fused ore certified reference materials. The accuracy and repeatability achieved are reported. Copyright © 2004 John Wiley & Sons, Ltd.

Neutron capillary optics: status and perspectives

The article is dedicated to the current status of neutron polycapillary optics and its application. X-ray and neutron polycapillary optics was first suggested in my papers published and patented about 20 years ago. The first X-ray lens was made about 20 years ago (in 1985) in my laboratory at the Kurchatov Institute of Atomic Power. The first neutron assembled capillary lens consisting of several thousand polycapillaries was assembled and tested 2 years later at the atomic reactor of the Kurchatov Institute. A great many experiments were done at the atomic reactors in Russia, Germany, France, USA for neutron beam focusing, turning. Most successful were the experiments on turning neutron beam at the atomic reactor in Berlin, where it was possible to turn the neutron beam by the angle of 20°. Numerous experiments in Germany and France proved high efficacy of polycapillary optics in controlling thermal neutron radiation. The article gives new results obtained in creating pure beams of thermal neutrons on the basis of polycapillary optics. New polycapillary technologies developed at IRO, Moscow/Unisantis, Geneva, enable creation of neutron diffractometers, spectrometers, reflectometers, microscopes—all with a micron-size focal spot. All instruments are portable and highly efficient. Such generation of instruments has been already developed and realized for X-rays, and the same process for neutron beams has already started. So, neutron polycapillary optics makes it possible to create new instruments and raise the level of scientific research, and also enables use of neutron beam for industrial application in production environment.

Neutron capillary optics: status and perspectives

The article is dedicated to the current status of neutron polycapillary optics and its application. X-ray and neutron polycapillary optics was first suggested in my papers published and patented about 20 years ago. The first X-ray lens was made about 20 years ago (in 1985) in my laboratory at the Kurchatov Institute of Atomic Power. The first neutron assembled capillary lens consisting of several thousand polycapillaries was assembled and tested 2 years later at the atomic reactor of the Kurchatov Institute. A great many experiments were done at the atomic reactors in Russia, Germany, France, USA for neutron beam focusing, turning. Most successful were the experiments on turning neutron beam at the atomic reactor in Berlin, where it was possible to turn the neutron beam by the angle of 20°. Numerous experiments in Germany and France proved high efficacy of polycapillary optics in controlling thermal neutron radiation. The article gives new results obtained in creating pure beams of thermal neutrons on the basis of polycapillary optics. New polycapillary technologies developed at IRO, Moscow/Unisantis, Geneva, enable creation of neutron diffractometers, spectrometers, reflectometers, microscopes—all with a micron-size focal spot. All instruments are portable and highly efficient. Such generation of instruments has been already developed and realized for X-rays, and the same process for neutron beams has already started. So, neutron polycapillary optics makes it possible to create new instruments and raise the level of scientific research, and also enables use of neutron beam for industrial application in production environment.

X-ray spectrometry using polycapillary X-ray optics and position sensitive detector

Polycapillary X-ray optics (capillary X-ray lens) are now popular in X-ray fluorescence (XRF) analysis. Such an X-ray lens can collect X-rays emitted from an X-ray source in a large solid angle and form a very intense X-ray microbeam which is very convenient for microbeam X-ray fluorescence (MXRF) analysis giving low minimum detection limits (MDLs) in energy dispersive X-ray fluorescence (EDXRF). A new method called position sensitive X-ray spectrometry (PSXS) which combines an X-ray lens used to form an intense XRF source and a position sensitive detector (PSD) used for wavelength dispersive spectrometry (WDS) measurement was developed recently in the X-ray Optics Laboratory of Institute of Low Energy Nuclear Physics (ILENP) at Beijing Normal University. Such a method can give high energy and spacial resolution and high detection efficiency simultaneously. A short view of development of both the EDXRF using a capillary X-ray lens and the new PSXS is given in this paper.

Cold neutron microprobe for materials analysis using tapered capillary optics

A prototype monolithic capillary lens for focusing neutrons produced by thermally drawing straight multicapillary bundles has been characterized with cold neutrons, and gives an intensity gain of a factor of 25 at a focal distance of 8 mm, over the focal spot area of width 87 μm. This is over an order of magnitude smaller in area than for the multifiber capillary lens. The spatial resolution available with the lens has been tested with prompt gamma measurements on slivers of dysprosium. Background problems that can affect the spatial resolution of measurements taken at the focal position of the lens are addressed. The boron glass of the tapered monolithic lens provides good shielding from unfocused neutrons in the vicinity of the lens focus.

Examination of the Excitation Performance of Different Capillary Optics

The use of X-ray optics allows for elemental analysis of small samples and small areas: particles, inclusions and elemental distributions. Previously, collimators have been used to limit the X-ray beam diameter. However, in recent years, glass capillary optics have come into use. X-rays propagate through a capillary optic by total reflection from the inner wall of the capillary. Furthermore, different types of capillary optics, mono-capillary and poly-capillary lenses, with distinct excitation properties are now available. Capillary optics alter the input tube spectrum due to the energy dependence of the critical angle of total reflection. Minimum beam diameter and the energy dependence of the beam diameter are also influenced by the conditions for total reflection. In this paper, the exciting performance of different X-ray optics are examined and compared to collimators.

Enhancement of optical luminescence of solids using a capillary lens

Enhancement of optical luminescence of solids using a capillary lens

On the structure of X-ray glass capillary lens focal spots

A capillary X-ray lense focal spot fine structure with one central spot surrounded by six neighbouring satellite spots was observed in Ref. [S.V. Nikitina, S.B. Dabagov, R.V. Fedorchuk, V.A. Murashova and M.N. Yakimenko, Proc. SPIE-2278 (1994) 191] and Ref. [S.V. Nikitina, N.S. Ibraimov, G.A. Vartaniants, A.N. Nikitin, L. Spielberger and S.B. Dabagov, Proc. SPIE-2278 (1994) 216] for a synchrotron source X-ray beam and was accounted for by X-ray interference. In this paper some estimates are given to verify whether transmission of X-rays through an array of glass capillaries could result in a stable interference pattern [S.B. Dabagov, M.A. Kumakhov and S.V. Nikitina, Phys. Lett. A 203 (1995) 279] capable of being recorded by a photographic plate. Simple considerations show that even very small tolerances on manufacturing precision of elements in the glass capillary assembly leads to a drastic decrease in coherency between the X-ray beams coming through different capillaries which destroys the interference pattern. In the paper a new geometrical optics explanation for the focal spot fine structure is proposed.

Interference phenomenon under focusing of synchrotron radiation by a Kumakhov lens

Results of experimental and theoretical studies on focusing of synchrotron radiation by means of capillary lenses are presented. For the explanation of the interference effect observed the wave the channeling theory is applied.