A5091349181- Advanced X-ray Imaging Techniques
- Advanced X-ray and CT Imaging
- Particle Detector Development and Performance
- Medical Imaging Techniques and Applications
- Advanced Electron Microscopy Techniques and Applications
- Advanced Semiconductor Detectors and Materials
- Photonic and Optical Devices
- Enzyme Structure and Function
- X-ray Spectroscopy and Fluorescence Analysis
- Advanced Fiber Laser Technologies
- Radiation Detection and Scintillator Technologies
- Advancements in Photolithography Techniques
- Microstructure and mechanical properties
- CCD and CMOS Imaging Sensors
- Electron and X-Ray Spectroscopy Techniques
- Metal and Thin Film Mechanics
- Advanced Fiber Optic Sensors
- Nuclear Physics and Applications
- Magnesium Alloys: Properties and Applications
- Semiconductor Lasers and Optical Devices
- Intermetallics and Advanced Alloy Properties
- Optical measurement and interference techniques
- Photonic Crystals and Applications
- High Temperature Alloys and Creep
- Carbon Nanotubes in Composites
Cornell University
2013-2022
University of Illinois Urbana-Champaign
2019
Wright-Patterson Air Force Base
2019
Argonne National Laboratory
2019
Institut Laue-Langevin
2008
Korea Atomic Energy Research Institute
2008
SPring-8
2008
Japan Synchrotron Radiation Research Institute
2008
Seikagaku Corporation (Japan)
2008
Rigaku (Japan)
2008
Size Matters Less X-ray crystallography is a central research tool for uncovering the structures of proteins and other macromolecules. However, its applicability typically requires growth large crystals, in part because sufficient number molecules must be present lattice sample to withstand x-ray—induced damage. Boutet et al. (p. 362 , published online 31 May) now demonstrate that intense x-ray pulses emitted by free-electron laser source can yield data few enough exposures uncover...
We describe a hybrid pixel array detector (EMPAD - electron microscope detector) adapted for use in applications, especially as universal scanning transmission microscopy. The 128 x consists of 500 um thick silicon diode bump-bonded pixel-by-pixel to an application-specific integrated circuit (ASIC). in-pixel circuitry provides 1,000,000:1 dynamic range within single frame, allowing the direct beam be imaged while still maintaining sensitivity. A 1.1 kHz framing rate enables rapid data...
Precision and accuracy of quantitative scanning transmission electron microscopy (STEM) methods such as ptychography, the mapping electric, magnetic, strain fields depend on dose. Reasonable acquisition time requires high beam current ability to quantitatively detect both large minute changes in signal. A new hybrid pixel array detector (PAD), second-generation Electron Microscope Pixel Array Detector (EMPAD-G2), addresses this challenge by advancing technology a previous generation PAD,...
The routine atomic resolution structure determination of single particles is expected to have profound implications for probing structure-function relationships in systems ranging from energy-storage materials biological molecules. Extremely bright ultrashort-pulse X-ray sources - free-electron lasers (XFELs) provide X-rays that can be used probe ensembles nearly identical nanoscale particles. When combined with coherent diffractive imaging, these objects imaged; however, as the images...
An x-ray pixel array detector (PAD) capable of framing up to 1 kHz is described. This hybrid constructed from a 3-side buttable, 128×128 module based upon the mixed-mode (MMPAD) chip developed jointly by Cornell and Area Detector Systems Corporation (Poway, CA). The uses charge integrating front end for high instantaneous count rate yet with single photon sensitivity. In-pixel circuitry utilizing digital overflow counter extends per frame dynamic range >4×107 x-rays/pixel. Results are shown...
The production of high-performance carbon nanotube (CNT) materials demands understanding the growth behavior individual CNTs as well collective effects among CNTs. We demonstrate first use grazing incidence small-angle X-ray scattering to monitor in real time synthesis CNT films by chemical vapor deposition. a custom-built cold-wall reactor along with high-speed pixel array detector resulting resolution 10 msec. Quantitative models applied time-resolved patterns reveal that Fe catalyst film...
Single-particle imaging experiments of biomolecules at x-ray free-electron lasers (XFELs) require processing hundreds thousands images that contain very few x-rays. Each low-fluence image the diffraction pattern is produced by a single, randomly oriented particle, such as protein. We demonstrate feasibility recovering structural information these extremes using 2D mask. Successful reconstruction obtained with averaging only 2.5 photons per frame, where it seems doubtful there could be about...
Coherent (X-ray) diffractive imaging (CDI) is an increasingly popular form of X-ray microscopy, mainly due to its potential produce high-resolution images and the lack objective lens between sample corresponding detector. One challenge, however, that very high dynamic range diffraction data must be collected both quantitative images. In this work, hard ptychographic coherent has been performed at P10 beamline PETRA III synchrotron demonstrate a wide detector (the Mixed-Mode Pixel Array...
Test results are presented of a pixel array detector (PAD) developed for x-ray imaging at the Stanford Linear Coherent Light Source (LCLS). The basic module PAD consists two bump-bonded chips: reverse-biased silicon diode chip 185 × 194 pixels, each which is coupled by bump-bonds to charge integrating CMOS ASIC with digitization in pixel. LCLS experiment requires high signal-to-noise ratio detection single 8 keV x-rays, full-well exceeding 1,000 frame-rate 120 Hz, and ability handle arrival...
A pixel array detector (PAD) module has been developed at Cornell University for the collection of diffuse diffraction data in anticipation coherent X-ray imaging experiments that will be conducted Linac Coherent Light Source (LCLS) SLAC National Accelerator Laboratory. The is designed to collect X-rays scattered from monochromatic femtosecond pulses produced by LCLS laser framing rates up 120 Hz. Because arrive on time scales, must able deal with instantaneous count-rates excess 1017...
Schemes for X-ray imaging single protein molecules using new x-ray sources, like free electron lasers (XFELs), require processing many frames of data that are obtained by taking temporally short snapshots identical molecules, each with a random and unknown orientation. Due to the small size exposure times, average signal levels much less than 1 photon/pixel/frame expected, too low be processed standard methods. One approach process is use statistical methods developed in EMC algorithm (Loh &...
We have developed two techniques for time-resolved x-ray diffraction from bulk polycrystalline materials during dynamic loading. In the first technique, we synchronize a fast detector with loading of samples at strain rates ∼103–104 s−1 in compression Kolsky bar (split Hopkinson pressure bar) apparatus to obtain situ patterns exposures as short 70 ns. This approach employs moderate energies (10–20 keV) and is well suited weakly absorbing such magnesium alloys. The second technique useful...
A wide-dynamic-range imaging X-ray detector designed for recording successive frames at rates up to 10 MHz is described. with frame of 6.5 have been experimentally verified. The pixel design allows 8-12 be stored internally high speed before readout, which occurs a 1 kHz rate. An additional mode operation the integration capacitors re-addressed repeatedly readout can enhance signal-to-noise ratio cyclical processes. This detector, along modern storage ring sources provide short (10-100 ps)...
Pixel Array Detectors (PADs) consist of an x-ray sensor layer bonded pixel-by-pixel to underlying readout chip. This approach allows both the and custom pixel electronics be tailored independently best match imaging requirements. Here we present characterizations CdTe sensors hybridized with two different charge-integrating chips, Keck PAD Mixed-Mode (MM-PAD), developed previously in our laboratory. The architecture each these PADs extends instantaneous counting rate by many orders magnitude...
X-ray serial microcrystallography involves the collection and merging of frames diffraction data from randomly oriented protein microcrystals. The number diffracted X-rays in each frame is limited by radiation damage, this decreases with crystal size. are said to be sparse if too few collected determine orientation microcrystal. It commonly assumed that cannot merged, thereby setting a lower limit size microcrystals may merged given source fluence. EMC algorithm [Loh & Elser (2009 ▶), Phys....
Several charge integrating CMOS pixel front-ends utilizing removal techniques have been fabricated to extend dynamic range for x-ray diffraction applications at synchrotron sources and free electron lasers (XFELs). The pixels described herein build on the Mixed Mode Pixel Array Detector (MM-PAD) framework, developed previously by our group perform high imaging. These new boast several orders of magnitude improvement in maximum flux over MM-PAD, which is capable measuring a sustained excess...
Abstract Long-standing evidence suggests that plasticity in metals may proceed an intermittent fashion. While the documentation of intermittency plastically deforming materials has been achieved several experimental settings, efforts to draw connections from dislocation motion and structure development stress relaxation have limited, especially bulk polycrystals. This work uses high energy x-ray diffraction measurements build these links by characterizing plastic deformation events inside...
Abstract We characterize a new x-ray Mixed-Mode Pixel Array Detector (MM-PAD-2.1) Application Specific Integrated Circuit (ASIC). Using an integrating pixel front-end with dynamic charge removal architecture, the MM-PAD-2.1 ASIC extends maximum measurable signal (in 20 keV photon units) to > 10 7 x-rays/pixel/frame while maintaining low read noise across full range, all imaging continuously at frame rate of up kHz. The in-pixel mechanism prevents saturation input amplifier and proceeds in...
Next generation light sources are revolutionizing x-ray science by delivering ultra-intense, hard pulses many orders of magnitude brighter and shorter in duration than previously achievable. Maximizing the scientific potential these requires development suitable detectors. Experiments such as coherent imaging single particles require detectors that can record extremely high instantaneous flux rates produced femtosecond (i.e. thousands photons incident on a pixel an area detector few...
A technique for measuring interdiffusion in multilayer materials during rapid heating using X-ray reflectivity is described. In this the sample bent to achieve a range of incident angles simultaneously, and scattered intensity recorded on fast high-dynamic-range mixed-mode pixel array detector. Heating achieved by electrical resistive silicon substrate, monitored an infrared pyrometer. As example, data from Al/Ni heated at rates up 200 K s-1 are presented. At short times coefficient can be...
Amorphous silicon rich nitride optical waveguides clad in silica are presented as a high-index contrast platform for high-density integrated optics. Performance of different cross-sectional geometries have been measured and with regards to bending loss insertion loss. A sample double ring add-drop filter is presented.
In recent years, the success of serial femtosecond crystallography and paucity beamtime at X-ray free-electron lasers have motivated development microcrystallography experiments storage-ring synchrotron sources. However, especially sources, if a crystal is too small it will suffered significant radiation damage before diffracting sufficient number X-rays into Bragg peaks for peak-indexing software to determine orientation. As consequence, data frames crystals often cannot be indexed are...
We have developed calibration and data processing techniques optimized specifically for photon-integrating pixel array detectors (PADs). Primary effects to be calibrated are gain variation area variation. Gain variations originate in electronics may corrected via a multiplicative factor. In contrast, result from doping inhomogeneities the sensor diode, which induce lateral fields that disturb path of charge carriers as they traverse resulting mapped each pixel, depending on x-ray energy....