Polycapillary Parallel X-ray Lens Research Articles

Numerical design and characterization of a novel parallel beam combined lens based on X-ray capillary optics

A novel parallel beam combined lens (PBCL) was designed based on a parabolic monocapillary x-ray lens (PMXRL). The proposed PBCL converted a divergent X-ray beam into a near-solid parallel one, which retains the low divergence characteristics of PMXRL and significantly improves the intensity gain by about one order of magnitude. Compared with the traditional polycapillary parallel x-ray lens (PPXRL), the divergence performance of this lens is improved by an order of magnitude, and the light intensity gain is improved by 3-4 times. In addition, we developed a MATLAB-based visualization tool to simulate X-ray transmission within the PBCL through ray tracing. This tool facilitated the assessment of the PBCL's transmission efficiency and its comparison with conventional PMXRL and the PPXRL. The transport process of the PBCL is systematically investigated under the comprehensive consideration of multiple parameters. This study provided a new idea and theoretical basis for the further development of X-ray modulation technology.

Research on a laboratory monochromatic micro X-ray fluorescence spectrometer based on polycapillary X-ray lenses and flat crystal

Monochromatic micro X-ray fluorescence (Mμ-XRF) analysis has the advantages of high resolution and low detection limit and is a powerful tool to obtain information on element distribution and concentration in materials. An Mμ-XRF spectrometer for laboratory X-ray tubes is developed in this paper, which mainly composed of an X-ray tube, two polycapillary X-ray lenses and a flat crystal. The polycapillary parallel X-ray lens converts the divergent broadband X-rays emitted by the X-ray tube into quasi-parallel X-rays and projects them onto a flat crystal, where monochromatic X-rays are obtained by crystal diffraction. The monochromatic X-rays are then focused by a polycapillary half-focusing X-ray lens to provide spatial resolution for fluorescence analysis. The combination of the two makes it possible to perform Mμ-XRF under laboratory low-power X-ray tube conditions (5.3 W molybdenum tube). By selecting polycapillary half-focusing X-ray lenses with different parameters, the spectrometer can provide a spatial resolution of tens to hundreds of microns to suit various application requirements. The detection limits of the Mμ-XRF spectrometer are also measured using standard solutions. Experimental results show that the detection limit of Se is 52 μg/L and that the detection limit for light elements such as Mn is 970 μg/L.

Theoretical Simulation of X-Ray Transmission Through a Polycapillary X-Ray Lens With a Variable Capillary Radius

This article presents a model for simulating the X-ray transmission properties of a polycapillary X-ray lens in which the capillaries are arranged in a layered hexagonal structure. Each layer consists of hexagonally shaped capillary bundles which are arranged symmetrically around a centerline, and the capillary radius varies with the layer. The transmission efficiency of X-rays in different layers is studied, and by designing the capillary radius, a uniform X-ray intensity distribution is generated at the output of the polycapillary parallel X-ray lens, which has remarkable differences with the distribution of a conventional polycapillary parallel X-ray lens. In addition, several common defects in the manufacturing process of the polycapillary lens are simulated.

Energy-dispersive small-angle X-ray scattering with cone collimation using X-ray capillary optics.

Energy-dispersive small-angle X-ray scattering (ED-SAXS) with an innovative design of cone collimation based on an ellipsoidal single-bounce capillary (ESBC) and a polycapillary parallel X-ray lens (PPXRL) had been explored. Using this new cone collimation system, scattering angle 2θ has a theoretical minimum angle related to the mean half-opening angle of the hollow cone beam of 1.42 mrad, and with the usable X-ray energy ranging from 4 to 30 keV, the resulting observable scattering vector q is down to a minimum value of about 0.003 Å-1 (or a Bragg spacing of about 2100 Å). However, the absorption of lower energies by X-ray capillary optics, sample transmission, and detector response function limits the application range to lower energy. Cone collimation ED-SAXS experiments carried out on pure water, Lupolen, and in situ temperature-dependent measurement of diacetylenic acid/melamine micelle solid were presented at three different scattering angles 2θ of 0.18°, 0.70° and 1.18° to illustrate the new opportunities offered by this technique as well as its limitations. Also, a comparison has been made by replacing the PPXRL with a pinhole, and the result shows that cone collimation ED-SAXS based on ESBC with PPXRL was helpful in improving the signal-to-noise ratio (i.e., reducing the parasitic background scattering) than ESBC with a pinhole. The cone collimation instrument based on X-ray capillary optics could be considered as a promising tool to perform SAXS experiments, especially cone collimation ED-SAXS has potential application for the in situ temperature-dependent studying on the kinetics of phase transitions.

Focal construct geometry for high intensity energy dispersive x-ray diffraction based on x-ray capillary optics.

We presented a focal construct geometry (FCG) method for high intensity energy dispersive X-ray diffraction by utilizing a home-made ellipsoidal single-bounce capillary (ESBC) and a polycapillary parallel X-ray lens (PPXRL). The ESBC was employed to focus the X-rays from a conventional laboratory source into a small focal spot and to produce an annular X-ray beam in the far-field. Additionally, diffracted polychromatic X-rays were confocally collected by the PPXRL attached to a stationary energy-resolved detector. Our FCG method based on ESBC and PPXRL had achieved relatively high intensity diffraction peaks and effectively narrowed the diffraction peak width which was helpful in improving the potential d-spacing resolution for material phase analysis.

Combined optic system based on polycapillary X-ray optics and single-bounce monocapillary optics for focusing X-rays from a conventional laboratory X-ray source

Two combined optic systems based on polycapillary X-ray optics and single-bounce monocapillary optics (SBMO) were designed for focusing the X-rays from a conventional laboratory X-ray source. One was based on a polycapillary focusing X-ray lens (PFXRL) and a single-bounce ellipsoidal capillary (SBEC), in which the output focal spot with the size of tens of micrometers of the PFXRL was used as the “virtual” X-ray source for the SBEC. The other system was based on a polycapillary parallel X-ray lens (PPXRL) and a single-bounce parabolic capillary (SBPC), in which the PPXRL transformed the divergent X-ray beam from an X-ray source into a quasi-parallel X-ray beam with the divergence of sever milliradians as the incident illumination of the SBPC. The experiment results showed that the combined optic systems based on PFXRL and SBEC with a Mo rotating anode X-ray generator with the focal spot with a diameter of 300μm could obtain a focal spot with the total gain of 14,300 and focal spot size of 37.4μm, and the combined optic systems based on PPXRL and SBPC with the same X-ray source mentioned above could acquire a focal spot with the total gain of 580 and focal spot size of 58.3μm, respectively. The two combined optic systems have potential applications in micro X-ray diffraction, micro X-ray fluorescence, micro X-ray absorption near edge structure, full field X-ray microscopes and so on.

A confocal three-dimensional micro X-ray scattering technology based on Rayleigh to Compton ratio for identifying materials with similar density and different weight percentages of low-Z elements

Abstract A point-by-point Rayleigh to Compton scattering ratio (R/C) imaging for two polymer materials with similar density and different weight percentages of low-Z elements was carried out by using the confocal three-dimensional (3D) micro X-ray scatter tomographic technology based on polycapillary X-ray optics. This confocal 3D micro X-ray scatter tomographic technique was based on the confocal configuration of a polycapillary focusing X-ray lens (PFXRL) in the excitation channel and a polycapillary parallel X-ray lens (PPXRL) in the detection channel, which let only the X-rays scattered from the confocal micro-volume overlapped by the input focal spot of the PPXRL and the output focal spot of the PFXRL be detected by the detector. The main scope of this study was using the confocal 3D micro X-ray scattering tomography based on the R/C ratio to characterize and identify materials with nearly equal low density and different weight percentages of low-Z elements, as other radiological techniques are difficult to discriminate them for their very close attenuation coefficients μ . A mapping of R/C ratios for two thermoplastic polymer materials was obtained, which provided the spatially resolved distribution of their effective atom numbers, and their differences were accordingly presented. This confocal 3D micro X-ray scatter tomographic technique has potential applications in fields such as material identification, dosimetry, medical imaging, carbonation cancer, and so on.

In situ analysis of electrocrystallization process of metal electrodeposition with confocal energy dispersive X-ray diffraction based on polycapillary X-ray optics

The confocal energy dispersive X-ray diffraction (EDXRD) based on a polycapillary focusing X-ray lens (PFXRL) in excitation channel and a polycapillary parallel X-ray lens (PPXRL) in detection channel was presented to study the electrocrystallization process of metal electrodeposition. The input focal spot of the PPXRL and the output focal spot of the PFXRL was adjusted in a confocal configuration, and only the X-rays from the volume overlapped by the two foci could be accordingly detected by the detector. The experimental results demonstrated the confocal EDXRD could be used to in situ real-time analysis of electrochemical crystal growth process.

Confocal three-dimensional micro X-ray scatter imaging for non-destructive detecting foreign bodies with low density and low-Z materials in food products

Confocal three-dimensional (3D) micro X-ray scatter imaging technology based on polycapillary X-ray optics was used to carry out a point-to-point image analysis of foreign bodies in food products which were consisting of low density materials with low-Z elements. This confocal 3D micro X-ray scatter imaging method was based on a polycapillary focusing X-ray lens (PFXRL) in the excitation channel and a polycapillary parallel X-ray lens (PPXRL) in the detection channel. The PFXRL and PPXRL were placed in a confocal configuration. This let only the X-rays scattered from the confocal micro-volume overlapped by the output focal spot of the PFXRL and the input focal spot of the PPXRL be detected by the detector. The aim of this study was to demonstrate the ability of confocal micro X-ray scattering technology based on polycapillary X-ray optics to discriminate foreign bodies which adulterated in food products, and also utilize this confocal micro X-ray scattering technology to present scattered X-ray imaging for them. This confocal 3D micro-beam X-ray scattering imaging technology has potential applications in such fields as food safety, agriculture, bio-pharmaceutical, Meat Science, and so on.

Application of polycapillary x ray lens to eliminate both the effect of x ray source size and scatter of the sample in laboratory tomography

A tomography device based on a conventional laboratory x ray source, polycapillary parallel x ray lens (PPXRL), and polycapillary collimating x ray lens (PCXRL) is designed. The PPXRL can collect the divergent x ray beam from the source and focus it into a quasi-parallel x ray beam with a divergence of 4.7 mrad. In the center of quasi-parallel x ray beam, there is a plateau region with an average gain in power density of 13.8 and a diameter of 630 μm. The contrast of the image can be improved from 28.9% to 56.0% after adding the PCXRL between the sample and the detector.

Application of confocal technology based on polycapillary X-ray optics in three-dimensional diffraction scanning analysis

The confocal technology based on a polycapillary focusing X-ray lens in the excitation channel and a polycapillary parallel X-ray lens in the detection channel was used to perform three-dimensional energy dispersive X-ray diffraction scanning analysis of a copper film on a silicon substrate. A theoretical model of correcting the intensity of the diffracted X-rays from different parts of the sample in the confocal volume was designed. The point-to-point 3D diffraction information of the sample was obtained.

Spatially Resolved In Situ Measurements of the Ion Distribution Near the Surface of Electrode in a Steady-State Diffusion in an Electrolytic Tank with Confocal Micro X-ray Fluorescence

Confocal micro-X-ray fluorescence (MXRF) technology based on a polycapillary focusing X-ray lens and a polycapillary parallel X-ray lens was used to carry out element-resolved and in situ analysis of ion distribution near the surface of the electrode in a steady-state diffusion in an electrolytic tank. The standard curve of the Cu Kα fluorescence intensity corresponding to the concentration of CuCl2 was measured to quantitatively determine the ion distribution near the surface of the electrode in a steady-state diffusion. The distribution of the electrolytic ions around the surface of the electrode in the electrolytic tank was measured in situ, and the effects of the concentration of the electrolyte and the bath voltage on the shape of the layer with a nonuniform distribution of the Cu(2+) ions near the cathode surface in a steady state were analyzed with the confocal MXRF. The confocal MXRF has potential applications in spatially resolved analysis of the liquid mass transfer in electrolytic tanks in situ.

Performance of polycapillary X-ray optics for confocal energy-dispersive small-angle X-ray scattering

A confocal energy-dispersive small-angle X-ray scattering (EDSAXS) setup based on polycapillary optics was designed. In this confocal EDSAXS setup, a polycapillary slightly focusing X-ray lens (PSFXRL) and a polycapillary parallel X-ray lens (PPXRL) with a long input focal distance were placed confocally in the excitation channel and detection channel, respectively. This confocal configuration was helpful in improving the signal-to-noise ratio of the EDSAXS. The high gain in power density of the PSFXRL and PPXRL decreased the power requirement of the X-ray source for EDSAXS. The confocal EDSAXS technology could be used to perform nondestructive andin situanalysis of samples such as milk powder in its packaging.

Performances for confocal X-ray diffraction technology based on polycapillary slightly focusing X-ray optics

The confocal X-ray diffraction (XRD) technology based on a polycapillary slightly focusing X-ray lens (PSFXRL) in excitation channel and a polycapillary parallel X-ray lens (PPXRL) with a long input focal distance in detection channel was developed. The output focal spot of the PSFXRL and the input focal spot of the PPXRL were adjusted in confocal configuration, and only the X-rays from the volume overlapped by these foci could be accordingly detected. This confocal configuration was helpful in decreasing background. The convergence of the beam focused by the PSFXRL and divergence of the beam which could be collected by the PPXRL with a long input focal distance were both about 9mrad at 8keV. This was helpful in improving the resolution of lattice spacing of this confocal XRD technology. The gain in power density of such PSFXRL and PPXRL was about 120 and 7 at 11keV, respectively, which was helpful in using the low power source to perform XRD analysis efficiently. The performances of this confocal XRD technology were provided, and some common plastics were analyzed. The experimental results demonstrated that the confocal diffraction technology base on polycapillary slightly focusing X-ray optics had wide potential applications.

Size-Resolved Source Apportionment of Aerosol Particles with a Confocal Micro X-Ray Fluorescence Spectrometer

A laboratory confocal micro X-ray fluorescence (micro-XRF) spectrometer based on a polycapillary focusing X-ray lens (PFXRL) in the excitation channel and a polycapillary parallel X-ray lens (PPXRL) in the detection channel was used to carry out the size-resolved source apportionment of aerosol particles. The PPXRL in the detection channel both increased the collection angle of the detector and improved the signal-to-noise ratio of the X-ray spectrum. When this confocal micro-XRF spectrometer was used to carry out the quantitative XRF analysis of single aerosol particles with smaller size than that of the overlapping foci of the PFXRL and the PPXRL, the sensitivity was corrected by using a Gaussian function. The size-resolved “fingerprint database” for the air pollution sources was established based on the quantitative XRF results for single aerosol particles. The size-resolved aerosol particles on hazy-foggy days in Beijing were apportioned.

Fine structures of divergence of polycapillary X-ray optics

The divergence of the beam focused by polycapillary X-ray optics (PXRO) varied at different distances from the exit of the PXRO. This distance dependence of the divergence of the PXRO was defined as the fine structures of the divergence of the PXRO. The fine structures of the divergence of the PXRO were presented in order to use them fully. There were main three types of the PXRO, such as polycapillary parallel X-ray lens (PPXRL), polycapillary focusing X-ray lens (PFXRL) and polycapillary slightly focusing X-ray lens (PSFXRL). For the PPXRL, the divergence decreased near its exit. The reason for this might be that the divergence near the exit of the PPXRL depended mainly on the X-rays traversing directly through the monocapillaries in the center of the PPXRL without total reflection. For the PFXRL and PSFXRL, they both had respectively a focal depth over which the beam sizes at different output distances remained acceptably small. For the 8 keV X-rays, the focal depth and divergence over the focal depth of the PFXRL were about 300 μm and 25.0 mrad, respectively. At the same energy of 8 keV, the focal depth and divergence over the focal depth of the PSFXRL were about 500 μm and 12.5 mrad, respectively. The divergence of the PFXRL and the PSFXRL depended mainly on the angles between axes of monocapillaries that composed them.

Performances of capillary X-ray optics for confocal three-dimensional micro-X-ray fluorescence technology

The performances of capillary X-ray optics (CXRO) for confocal three-dimensional micro-X-ray fluorescence (3D Micro-XRF) technology are presented. In particular, the energy dependence of the collecting angle and input focal spot size of the polycapillary parallel X-ray lens (PPXRL), and the energy dependence of spatial resolution of the confocal 3D Micro-XRF spectrometer based on the CXRO are reported. In order to obtain the input focal spot size of the PPXRL, the source scan method was used. The size of the input focal spot of the PPXRL was 25.5μm at 13keV, and it was close to that of the output focal spot of a polycapillary focusing X-ray lens (PFXRL) at the same energy. The collecting angle of the PPXRL was 110mrad at 10keV, and it decreased with the increasing energies. The depth spatial resolution of the confocal 3D Micro-XRF spectrometer based on the CXRO was 29.3μm at 17keV, and it decreased with the increasing energies. The minimal detection limit of this confocal 3D Micro-XRF spectrometer was 101ppm for the Ti-Kα, when the operating voltage and current of the Mo X-ray tube were 36.0kV and 800.0μA, respectively.

Characterization of polycapillary X-ray lens for application in confocal three-dimensional energy-dispersive micro X-ray diffraction experiments

A confocal technology based on polycapillary X-ray optics is proposed to perform three-dimensional energy-dispersive micro X-ray diffraction. A three-dimensional energy-dispersive micro X-ray diffractometer based on a polycapillary focusing X-ray lens (PFXRL) in the excitation channel and a polycapillary parallel X-ray lens (PPXRL) in the detection channel has been designed. At 2\theta = 90^ \circ, the lateral resolution l_X \times l_Y of this diffractometer is 49.7 \times 49.9 \rm \micro m at 7.5 keV, and its depth resolution d_Z is 48.1 \rm \micro m at 8.0 keV. The total resolution of this diffractometer in \Delta d/d is 6.5% at 6.4 keV and 2\theta = 140.2^ \circ.

An energy dispersive micro X-ray diffractometer based on a combined system of polycapillary optics

An energy dispersive micro X-ray diffractometer based on a combined system of two polycapillary X-ray lenses is designed. The polycapillary X-ray lens in the excitation channel is either a polycapillary parallel X-ray lens (PPXRL) or a slightly focusing polycapillary X-ray lens (SFPXRL). The polycapillary X-ray lens in the detection channel is a PPXRL. At 6.4 keV and 2 θ = 141.5°, the total resolution of the diffractometer based on a SFPXRL in the excitation channel and a PPXRL in the detection channel in Δ d/ d is 4.8%.