Abstract: In a method of preparing a single molecule sample of a biological material for use in an imaging experiment, the single molecule sample is deposited on a graphene substrate using a method such as nanopipetting. Excess bulk fluid surrounding the molecule is then removed, for example, by mechanical blotting or controlled evaporation. An enclosing layer of graphene is then deposited and sealed to the graphene substrate so as to encapsulate the molecule. This sealing may include floating the enclosing layer in a water bath and moving it into contact with the graphene substrate. The molecule of interest may be deposited directly on the substrate, or a linker molecule may be first deposited to provide an attachment between the substrate and the molecule of interest.

Abstract: An X-ray laser has a target anode of a crystalline material that emits X-ray radiation in response to excitation and that is located on a thermally conductive substrate. An X-ray source provides an input X-ray beam that illuminates a predetermined volume of the target anode at a predefined angle relative to a surface of the anode so as to induce a Borrmann mode standing wave in the predetermined volume. An electron source outputs an electron beam that is incident on the Borrmann mode region so as to cause electron impact ionization of the crystalline material and thereby induce stimulated emission of a coherent output X-ray beam.

Abstract: An X-ray laser has a target anode of a crystalline material that emits X-ray radiation in response to excitation and that is located on a thermally conductive substrate. An X-ray source provides an input X-ray beam that illuminates a predetermined volume of the target anode at a predefined angle relative to a surface of the anode so as to induce a Borrmann mode standing wave in the predetermined volume. An electron source outputs an electron beam that is incident on the Borrmann mode region so as to cause electron impact ionization of the crystalline material and thereby induce stimulated emission of a coherent output X-ray beam.

Abstract: An analytical X-ray tube with an anode target material that emits characteristic X-rays in response to excitation by an electron beam may include any of several advantageous features. The target material is deposited on a diamond substrate layer, and a metal carbide intermediate layer may be provided between the target material and substrate that provides enhanced bonding therebetween. An interface layer may also be used that provides an acoustic impedance matching between the target material and the substrate. For a low thermal conductivity target material, a heat dissipation layer of a higher thermal conductivity material may also be included between the target material and substrate to enhance thermal transfer. The target material may have a thickness that corresponds to a maximum penetration depth of the electrons of the electron beam, and the structure may be such that a predetermined temperature range is maintained at the substrate interface.

Abstract: An electron diffraction imaging system for imaging the three-dimensional structure of a single target molecule of a sample uses an electron source that emits a beam of electrons toward the sample, and a two-dimensional detector that detects electrons diffracted by the sample and generates an output indicative of their spatial distribution. A sample support is transparent to electrons in a region in which the sample is located, and is rotatable and translatable in at least two perpendicular directions. The electron beam has an operating energy between 5 keV and 30 keV, and beam optics block highly divergent electrons to limit the beam diameter to no more than three times the size of the sample molecule and provide a lateral coherence length of at least 15 nm. An adjustment system adjusts the sample support position in response to the detector output to center the target molecule in the beam.

Abstract: An electron diffraction imaging system for imaging the three-dimensional structure of a single target molecule of a sample uses an electron source that emits a beam of electrons toward the sample, and a two-dimensional detector that detects electrons diffracted by the sample and generates an output indicative of their spatial distribution. A sample support is transparent to electrons in a region in which the sample is located, and is rotatable and translatable in at least two perpendicular directions. The electron beam has an operating energy between 5 keV and 30 keV, and beam optics block highly divergent electrons to limit the beam diameter to no more than three times the size of the sample molecule and provide a lateral coherence length of at least 15 nm. An adjustment system adjusts the sample support position in response to the detector output to center the target molecule in the beam.

Abstract: An X-ray source uses excitation of a liquid metal beam of ions or ionized droplets to produce an X-ray output with higher brightness than conventional sources. The beam may be accelerated from a liquid metal source using an extraction electrode. The source may have an emitter tip, and the acceleration of the liquid metal may include field emission from a Taylor cone. An electrostatic or electromagnetic focusing electrode may be used to reduce a cross-sectional diameter of the beam. The liquid metal beam has a relatively high velocity as it does not suffer from flow turbulence, thus allowing for a more energetic excitation and a correspondingly higher brightness. A beam dump may also be used to collect the liquid metal beam after excitation, and may be concave with no direct sight lines to either an electron beam cathode or to X-ray windows of an enclosure for the source.

Abstract: An indirect, photon-counting X-ray detector capable of detecting the low-energy X-rays includes a scintillator screen that is directly coupled to a two-dimensional optical sensor. A signal filter receives an electrical output signal from the optical sensor and removes high intensity signal contributions therefrom that are indicative of direct interaction between said X-ray signal and said optical sensor. The scintillator screen has a sufficient thickness to ensure a high absorption of incident X-ray photons, and uses phosphor grains with a relatively small grain size. A cooling apparatus in thermal communication with the optical sensor may be used to control its temperature. The signal filter maintains a running average of changes in measured pixel output values for consecutive measurements, and replaces a measured value caused by a direct interaction event with a value equal to a previous measured value plus said running average.

Abstract: An X-ray source uses excitation of a liquid metal beam of ions or ionized droplets to produce an X-ray output with higher brightness than conventional sources. The beam may be accelerated from a liquid metal source using an extraction electrode. The source may have an emitter tip, and the acceleration of the liquid metal may include field emission from a Taylor cone. An electrostatic or electromagnetic focusing electrode may be used to reduce a cross-sectional diameter of the beam. The liquid metal beam has a relatively high velocity as it does not suffer from flow turbulence, thus allowing for a more energetic excitation and a correspondingly higher brightness. A beam dump may also be used to collect the liquid metal beam after excitation, and may be concave with no direct sight lines to either an electron beam cathode or to X-ray windows of an enclosure for the source.

Abstract: An analytical X-ray tube with an anode target material that emits characteristic X-rays in response to excitation by an electron beam may include any of several advantageous features. The target material is deposited on a diamond substrate layer, and a metal carbide intermediate layer may be provided between the target material and substrate that provides enhanced bonding therebetween. An interface layer may also be used that provides an acoustic impedance matching between the target material and the substrate. For a low thermal conductivity target material, a heat dissipation layer of a higher thermal conductivity material may also be included between the target material and substrate to enhance thermal transfer. The target material may have a thickness that corresponds to a maximum penetration depth of the electrons of the electron beam, and the structure may be such that a predetermined temperature range is maintained at the substrate interface.

Abstract: An indirect, photon-counting X-ray detector capable of detecting the low-energy X-rays includes a scintillator screen that is directly coupled to a two-dimensional optical sensor. A signal filter receives an electrical output signal from the optical sensor and removes high intensity signal contributions therefrom that are indicative of direct interaction between said X-ray signal and said optical sensor. The scintillator screen has a sufficient thickness to ensure a high absorption of incident X-ray photons, and uses phosphor grains with a relatively small grain size. A cooling apparatus in thermal communication with the optical sensor may be used to control its temperature. The signal filter maintains a running average of changes in measured pixel output values for consecutive measurements, and replaces a measured value caused by a direct interaction event with a value equal to a previous measured value plus said running average.

Abstract: A method for X-ray detection using a charge-integrating X-ray detector including a photodetector array of pixels, each of which converts incident radiation into accumulated charge during an X-ray exposure, is provided. The method includes, for each pixel, reading out the accumulated charge from the pixel and determining an X-ray charge value from the read out accumulated charge. If the X-ray charge value is less than a photon counting threshold, the X-ray charge value is replaced with a quantized charge value representative of an estimated photon count and recording the quantized charge value as a recorded charge value. If, however, the X-ray charge is equal to or greater than the photon counting threshold, the X-charge value is recorded as the recorded charge value. The method allows operating a charge-integrating X-ray detector in a mixed photon-counting/analog output mode.

Abstract: In an X-ray detector operating in a rolling shutter read out mode, by precisely synchronizing sample rotation with the detector readout, the effects of timing skew on the image intensities and angular positions caused by the rolling shutter read out can be compensated by interpolation or calculation, thus allowing the data to be accurately integrated with conventional software. In one embodiment, the reflection intensities are interpolated with respect to time to recreate data that is synchronized to a predetermined time. This interpolated data can then be processed by any conventional integration routine to generate a 3D model of the sample. In another embodiment a 3D integration routine is specially adapted to allow the time-skewed data to be processed directly and generate a 3D model of the sample.

Abstract: A method for X-ray detection using a charge-integrating X-ray detector including a photodetector array of pixels, each of which converts incident radiation into accumulated charge during an X-ray exposure, is provided. The method includes, for each pixel, reading out the accumulated charge from the pixel and determining an X-ray charge value from the read out accumulated charge. If the X-ray charge value is less than a photon counting threshold, the X-ray charge value is replaced with a quantized charge value representative of an estimated photon count and recording the quantized charge value as a recorded charge value. If, however, the X-ray charge is equal to or greater than the photon counting threshold, the X-charge value is recorded as the recorded charge value. The method allows operating a charge-integrating X-ray detector in a mixed photon-counting/analog output mode.

Abstract: A detector for a small-angle x-ray diffraction system uses curved readout strips shaped to correspond to the expected intensity distribution of x-rays scattered by the system. This expected intensity distribution may be a series of concentric circles, and each of the strips has a shape that approximates a section of an annulus. The strips may be positioned on a substrate such that a center of curvature of the curved strips is located along an edge of a readout region within which the strips are located or, alternatively, at a geometric center of the readout region. The detector may have a signal readout system that uses a delay line or, alternatively, a multichannel readout system. The detector may make use of electron generation via interaction of the diffracted x-ray beam with a gas in a gas chamber, or through interaction of the diffracted beam with a semiconductor material.

Abstract: In an X-ray detector operating in a rolling shutter read out mode, by precisely synchronizing sample rotation with the detector readout, the effects of timing skew on the image intensities and angular positions caused by the rolling shutter read out can be compensated by interpolation or calculation, thus allowing the data to be accurately integrated with conventional software. In one embodiment, the reflection intensities are interpolated with respect to time to recreate data that is synchronized to a predetermined time. This interpolated data can then be processed by any conventional integration routine to generate a 3D model of the sample. In another embodiment a 3D integration routine is specially adapted to allow the time-skewed data to be processed directly and generate a 3D model of the sample.

Abstract: In an X-ray detector operating in a rolling shutter read out mode, by precisely synchronizing sample rotation with the detector readout, the effects of timing skew on the image intensities and angular positions caused by the rolling shutter read out can be compensated by interpolation or calculation, thus allowing the data to be accurately integrated with conventional software. In one embodiment, the reflection intensities are interpolated with respect to time to recreate data that is synchronized to a predetermined time. This interpolated data can then be processed by any conventional integration routine to generate a 3D model of the sample. In another embodiment a 3D integration routine is specially adapted to allow the time-skewed data to be processed directly and generate a 3D model of the sample.

Abstract: A detector for a small-angle x-ray diffraction system uses curved readout strips shaped to correspond to the expected intensity distribution of x-rays scattered by the system. This expected intensity distribution may be a series of concentric circles, and each of the strips has a shape that approximates a section of an annulus. The strips may be positioned on a substrate such that a center of curvature of the curved strips is located along an edge of a readout region within which the strips are located or, alternatively, at a geometric center of the readout region. The detector may have a signal readout system that uses a delay line or, alternatively, a multichannel readout system. The detector may make use of electron generation via interaction of the diffracted x-ray beam with a gas in a gas chamber, or through interaction of the diffracted beam with a semiconductor material.

Abstract: Readout noise for each pixel in a CMOS Active Pixel Sensor is reduced by a five step process in which the pixel charge data from the sensor is non-destructively sampled at a plurality of times during a sensor frame time period and corrected for gain variation and nonlinearity. Then fixed pattern and dark current noise is estimated and subtracted from the corrected pixel charge data. Next, reset noise is estimated and subtracted from the pixel charge data. In step four, a model function of charge versus time is fit to the corrected pixel charge data samples. Finally, the fitted model function is evaluated at frame boundary times.

Abstract: Readout noise for each pixel in a CMOS Active Pixel Sensor is reduced by a five step process in which the pixel charge data from the sensor is non-destructively sampled at a plurality of times during a sensor frame time period and corrected for gain variation and nonlinearity. Then fixed pattern and dark current noise is estimated and subtracted from the corrected pixel charge data. Next, reset noise is estimated and subtracted from the pixel charge data. In step four, a model function of charge versus time is fit to the corrected pixel charge data samples. Finally, the fitted model function is evaluated at frame boundary times.