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Papers by mio lklkk

We have developed a x-ray microprobe in the energy region from 6 to 20 keV using undulator radiat... more We have developed a x-ray microprobe in the energy region from 6 to 20 keV using undulator radiation and zone-plate optics for microfocusing-based techniques and applications at a beamline at the Advanced Photon Source (APS). The performance of the beamline was shown to meet our design objectives, including preservation of the source brilliance and coherence, selectable transverse coherence length and

Review of Scientific Instruments, 2005

We describe progress in the fabrication of short-focal-length total-external-reflection Kirkpatri... more We describe progress in the fabrication of short-focal-length total-external-reflection Kirkpatrick-Baez x-ray mirrors with ultralow figure errors. The short focal length optics produce nanoscale beams (<100nm) on conventional (˜64m long) beamlines at third generation synchrotron sources. The total-external reflection optics are inherently achromatic and efficiently focus a white (polychromatic) or a tunable monochromatic spectrum of x rays. The ability to focus independent of wavelength allows novel new experimental capabilities. Mirrors have been fabricated both by computer assisted profiling (differential polishing) and by profile coating (coating through a mask onto ultra-smooth surfaces). A doubly focused 85×95nm2 hard x-ray nanobeam has been obtained on the UNICAT beamline 34-ID at the Advanced Photon Source. The performance of the mirrors, techniques for characterizing the spot size, and factors limiting focusing performance are discussed.

Applied Physics A-materials Science & Processing, 2010

The high source intensity of the Spallation Neutron Source (SNS), together with efficient detecto... more The high source intensity of the Spallation Neutron Source (SNS), together with efficient detectors and large detector solid angles, now makes possible neutron experiments with much smaller sample volumes than previously were practical. Nested Kirkpatrick–Baez supermirror optics provide a promising and efficient way to further decrease the useable neutron sample size by focusing polychromatic neutrons into microbeams. Because the optics are nondispersive, they are ideal for spallation sources and for polychromatic and wide bandpass experiments on reactor sources. Theoretical calculations indicate that nested mirrors can preserve source brilliance at the sample for small beams and for modest divergences that are appropriate for diffraction experiments. Although the flux intercepted by a sample can be similar with standard beam-guided approaches, the signal-to-background is much improved with small beams on small samples. Here we describe the design, calibration and performance of a nested neutron mirror pair for the Spallation Neutrons At Pressure (SNAP) beamline at the SNS. High-pressure neutron diffraction is but one example of a large class of neutron experiments that will benefit from spatially-resolved microdiffraction.

Beryllium windows are used on many X-ray synchrotron beamlines to separate and protect the ultra-... more Beryllium windows are used on many X-ray synchrotron beamlines to separate and protect the ultra-high vacuum of the storage ring from the experimental environment. Currently, such a window is typically made of a thin, high-purity, beryllium foil, which may or may not have been polished. It is well known that these windows affect the transmitted beam quality. The impact ranges from non-perceptible to profound, depending on the experiment. The degradation of the X-ray beam is of increasing importance and concern, however, and in fact a number of beamlines now are run windowless or with a very small and thin silicon nitride window. There remain many instances where a large and robust window is desirable or necessary, and it is for this reason that developing windows that have little or no impact on the transmitted X-ray beam quality is important. This presentation reports on the progress in developing single-crystal beryllium X-ray windows. Due to its high purity and homogeneity, relative structural perfection, and high polishiblity single-crystal beryllium is an attractive window material candidate, particularly for beamlines conducting imaging or coherence-based experiments. Development of thin and uniform windows with less than 1 nm rms surface roughness and their preliminary characterization results are presented.

Kirkpatrick-Baez (KB) mirrors consist of two individual mirrors: one vertical focusing mirror and... more Kirkpatrick-Baez (KB) mirrors consist of two individual mirrors: one vertical focusing mirror and one horizontal mirror at separate positions. Nested (Montel) KB mirrors consist of two mirrors arranged perpendicularly to each other and side-by-side. We report our results from the fabrication and tests of the first set of nested KB mirrors for a synchrotron hard x-ray micro/nano-focusing system. The elliptically shaped nested Platinum KB mirrors include two 40 mm long mirrors fabricated by depositing Platinum on Silicon substrates using the magnetron sputtering technique. Hard x-ray synchrotron tests have been performed at 15 keV and 2D focal spots of approximately 150 nm x 150 nm (FWHM) were achieved from both monochromatic and polychromatic beams at the 34 ID beamline of the Advanced Photon Source (APS) at Argonne National Laboratory. The side-by-side arrangement of nested KB mirrors requires them to have good surfaces and low figure errors at the intersection of the two mirrors' surfaces. It is very challenging to fabricate substrates that fit the nested KB mirror's arrangement and to deposit thin films to ideal elliptical shapes at the edge of the mirrors. Further research and development will be performed in the areas of fabrication and testing with respect to nested KB mirrors used in micro/nano-focusing systems. In particular, substrate processing and deposition techniques should be examined to improve the performance of the mirrors.

We report a successful fabrication and testing of the first set of Platinum (Pt)-coated Kirkpatri... more We report a successful fabrication and testing of the first set of Platinum (Pt)-coated Kirkpatrik-Baez (KB) mirrors for a submicrofocusing x-ray polychromatic beam from a conventional beamline (64 m long) at the 34-ID of Advanced Photon Source (APS). The set includes one 80 mm long mirror and one 40 mm short mirror fabricated by depositing Pt on finely polished spherical Silicon (Si) substrates using the APS-developed profile coating technique with the magnetron sputtering system. Profile coating masks were calculated through the coating profile data from metrology measurements acquired using interferometric stitching technique. Instead of flat substrates, spherical substrates (with shapes approximately mimicking the tangential profiles of the desired ellipses) were used, reducing the coating thickness and, thus, stress. The mirror pair was commissioned on the beamline and generated a 2-D spot with full width at half maximum (FWHM) 280 nm (V) x 150 nm (H). The detailed fabrication methods, metrology measurements, and calculations are discussed.

This paper presents the first series of round-robin metrology measurements of x-ray mirrors organ... more This paper presents the first series of round-robin metrology measurements of x-ray mirrors organized at the Advanced Photon Source (APS) in the USA, the European Synchrotron Radiation Facility in France, and the Super Photon Ring (SPring-8) (in a collaboration with Osaka University,) in Japan. This work is part of the three institutions' three-way agreement to promote a direct exchange of research information and experience amongst their specialists. The purpose of the metrology round robin is to compare the performance and limitations of the instrumentation used at the optical metrology laboratories of these facilities and to set the basis for establishing guidelines and procedures to accurately perform the measurements. The optics used in the measurements were selected to reflect typical, as well as state of the art, in mirror fabrication. The first series of the round robin measurements focuses on flat and cylindrical mirrors with varying sizes and quality. Three mirrors (two flats and one cylinder) were successively measured using long trace profilers. Although the three facilities' LTPs are of different design, the measurements were found to be in excellent agreement. The maximum discrepancy of the rms slope error values is 0.1 μrad, that of the rms shape error was 3 nm, and they all relate to the measurement of the cylindrical mirror. The next round-robin measurements will deal with elliptical and spherical optics.

Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2007

Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2007

An experimenter using an undulator beamline expects a Gaussian beam profile in two dimensions. Us... more An experimenter using an undulator beamline expects a Gaussian beam profile in two dimensions. Using a pinhole camera, one can measure the source size and orientation. With a camera placed far away from the source, one can measure the beam profile and estimate the source divergence. The camera can also reveal a possible tilt of the beam. In late 2005, we observed a tilt of 7∘ on the beam profile of the 7ID beamline, 51.5m from the source at the Advanced Photon Source (APS). A pinhole camera measurement revealed a source tilt of only about 1∘. These two separate measurements implied a tilt in the divergence of the beam. The source and divergence tilts may vary for each source point of the APS. We will discuss the implication of these tilts on the performance of an insertion device beamline at the APS.

We have developed a x-ray microprobe in the energy region from 6 to 20 keV using undulator radiat... more We have developed a x-ray microprobe in the energy region from 6 to 20 keV using undulator radiation and zone-plate optics for microfocusing-based techniques and applications at a beamline at the Advanced Photon Source (APS). The performance of the beamline was shown to meet our design objectives, including preservation of the source brilliance and coherence, selectable transverse coherence length and

Review of Scientific Instruments, 2005

We describe progress in the fabrication of short-focal-length total-external-reflection Kirkpatri... more We describe progress in the fabrication of short-focal-length total-external-reflection Kirkpatrick-Baez x-ray mirrors with ultralow figure errors. The short focal length optics produce nanoscale beams (<100nm) on conventional (˜64m long) beamlines at third generation synchrotron sources. The total-external reflection optics are inherently achromatic and efficiently focus a white (polychromatic) or a tunable monochromatic spectrum of x rays. The ability to focus independent of wavelength allows novel new experimental capabilities. Mirrors have been fabricated both by computer assisted profiling (differential polishing) and by profile coating (coating through a mask onto ultra-smooth surfaces). A doubly focused 85×95nm2 hard x-ray nanobeam has been obtained on the UNICAT beamline 34-ID at the Advanced Photon Source. The performance of the mirrors, techniques for characterizing the spot size, and factors limiting focusing performance are discussed.

Applied Physics A-materials Science & Processing, 2010

The high source intensity of the Spallation Neutron Source (SNS), together with efficient detecto... more The high source intensity of the Spallation Neutron Source (SNS), together with efficient detectors and large detector solid angles, now makes possible neutron experiments with much smaller sample volumes than previously were practical. Nested Kirkpatrick–Baez supermirror optics provide a promising and efficient way to further decrease the useable neutron sample size by focusing polychromatic neutrons into microbeams. Because the optics are nondispersive, they are ideal for spallation sources and for polychromatic and wide bandpass experiments on reactor sources. Theoretical calculations indicate that nested mirrors can preserve source brilliance at the sample for small beams and for modest divergences that are appropriate for diffraction experiments. Although the flux intercepted by a sample can be similar with standard beam-guided approaches, the signal-to-background is much improved with small beams on small samples. Here we describe the design, calibration and performance of a nested neutron mirror pair for the Spallation Neutrons At Pressure (SNAP) beamline at the SNS. High-pressure neutron diffraction is but one example of a large class of neutron experiments that will benefit from spatially-resolved microdiffraction.

Beryllium windows are used on many X-ray synchrotron beamlines to separate and protect the ultra-... more Beryllium windows are used on many X-ray synchrotron beamlines to separate and protect the ultra-high vacuum of the storage ring from the experimental environment. Currently, such a window is typically made of a thin, high-purity, beryllium foil, which may or may not have been polished. It is well known that these windows affect the transmitted beam quality. The impact ranges from non-perceptible to profound, depending on the experiment. The degradation of the X-ray beam is of increasing importance and concern, however, and in fact a number of beamlines now are run windowless or with a very small and thin silicon nitride window. There remain many instances where a large and robust window is desirable or necessary, and it is for this reason that developing windows that have little or no impact on the transmitted X-ray beam quality is important. This presentation reports on the progress in developing single-crystal beryllium X-ray windows. Due to its high purity and homogeneity, relative structural perfection, and high polishiblity single-crystal beryllium is an attractive window material candidate, particularly for beamlines conducting imaging or coherence-based experiments. Development of thin and uniform windows with less than 1 nm rms surface roughness and their preliminary characterization results are presented.

Kirkpatrick-Baez (KB) mirrors consist of two individual mirrors: one vertical focusing mirror and... more Kirkpatrick-Baez (KB) mirrors consist of two individual mirrors: one vertical focusing mirror and one horizontal mirror at separate positions. Nested (Montel) KB mirrors consist of two mirrors arranged perpendicularly to each other and side-by-side. We report our results from the fabrication and tests of the first set of nested KB mirrors for a synchrotron hard x-ray micro/nano-focusing system. The elliptically shaped nested Platinum KB mirrors include two 40 mm long mirrors fabricated by depositing Platinum on Silicon substrates using the magnetron sputtering technique. Hard x-ray synchrotron tests have been performed at 15 keV and 2D focal spots of approximately 150 nm x 150 nm (FWHM) were achieved from both monochromatic and polychromatic beams at the 34 ID beamline of the Advanced Photon Source (APS) at Argonne National Laboratory. The side-by-side arrangement of nested KB mirrors requires them to have good surfaces and low figure errors at the intersection of the two mirrors' surfaces. It is very challenging to fabricate substrates that fit the nested KB mirror's arrangement and to deposit thin films to ideal elliptical shapes at the edge of the mirrors. Further research and development will be performed in the areas of fabrication and testing with respect to nested KB mirrors used in micro/nano-focusing systems. In particular, substrate processing and deposition techniques should be examined to improve the performance of the mirrors.

We report a successful fabrication and testing of the first set of Platinum (Pt)-coated Kirkpatri... more We report a successful fabrication and testing of the first set of Platinum (Pt)-coated Kirkpatrik-Baez (KB) mirrors for a submicrofocusing x-ray polychromatic beam from a conventional beamline (64 m long) at the 34-ID of Advanced Photon Source (APS). The set includes one 80 mm long mirror and one 40 mm short mirror fabricated by depositing Pt on finely polished spherical Silicon (Si) substrates using the APS-developed profile coating technique with the magnetron sputtering system. Profile coating masks were calculated through the coating profile data from metrology measurements acquired using interferometric stitching technique. Instead of flat substrates, spherical substrates (with shapes approximately mimicking the tangential profiles of the desired ellipses) were used, reducing the coating thickness and, thus, stress. The mirror pair was commissioned on the beamline and generated a 2-D spot with full width at half maximum (FWHM) 280 nm (V) x 150 nm (H). The detailed fabrication methods, metrology measurements, and calculations are discussed.

This paper presents the first series of round-robin metrology measurements of x-ray mirrors organ... more This paper presents the first series of round-robin metrology measurements of x-ray mirrors organized at the Advanced Photon Source (APS) in the USA, the European Synchrotron Radiation Facility in France, and the Super Photon Ring (SPring-8) (in a collaboration with Osaka University,) in Japan. This work is part of the three institutions' three-way agreement to promote a direct exchange of research information and experience amongst their specialists. The purpose of the metrology round robin is to compare the performance and limitations of the instrumentation used at the optical metrology laboratories of these facilities and to set the basis for establishing guidelines and procedures to accurately perform the measurements. The optics used in the measurements were selected to reflect typical, as well as state of the art, in mirror fabrication. The first series of the round robin measurements focuses on flat and cylindrical mirrors with varying sizes and quality. Three mirrors (two flats and one cylinder) were successively measured using long trace profilers. Although the three facilities' LTPs are of different design, the measurements were found to be in excellent agreement. The maximum discrepancy of the rms slope error values is 0.1 μrad, that of the rms shape error was 3 nm, and they all relate to the measurement of the cylindrical mirror. The next round-robin measurements will deal with elliptical and spherical optics.

Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2007

Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2007

An experimenter using an undulator beamline expects a Gaussian beam profile in two dimensions. Us... more An experimenter using an undulator beamline expects a Gaussian beam profile in two dimensions. Using a pinhole camera, one can measure the source size and orientation. With a camera placed far away from the source, one can measure the beam profile and estimate the source divergence. The camera can also reveal a possible tilt of the beam. In late 2005, we observed a tilt of 7∘ on the beam profile of the 7ID beamline, 51.5m from the source at the Advanced Photon Source (APS). A pinhole camera measurement revealed a source tilt of only about 1∘. These two separate measurements implied a tilt in the divergence of the beam. The source and divergence tilts may vary for each source point of the APS. We will discuss the implication of these tilts on the performance of an insertion device beamline at the APS.