Results 1 - 10 of 5756
Results 1 - 10 of 5756. Search took: 0.038 seconds
|Sort by: date | relevance|
[en] We demonstrated the Talbot effect using a broadband hard x-ray beam (Δλ/λ ∼1). The exit wave-field of the x-ray beam passing through a grating with a sub micro-meter scale period was successfully replicated and recorded at effective Talbot distance, ZT. The period was reduced to half at ZT/4 and 3/4ZT, and the phase reversal was observed at ZT/2. The propagating wave-field recorded on photoresists was consistent with a simulated result.
[en] The macromolecular crystallography beamline MX1 at the Australian Synchrotron is described. MX1 is a bending-magnet crystallography beamline at the 3 GeV Australian Synchrotron. The beamline delivers hard X-rays in the energy range from 8 to 18 keV to a focal spot at the sample position of 120 µm FWHM. The beamline endstation and ancillary equipment facilitate local and remote access for both chemical and biological macromolecular crystallography. Here, the design of the beamline and endstation are discussed. The beamline has enjoyed a full user program for the last seven years and scientific highlights from the user program are also presented
[en] We report on high-resolution optical and hard X-ray observations of solar flare ribbons seen during the GOES X6.5 class white-light flare of 2006 December 6. The data consist of imaging observations at 430 nm (the Fraunhofer G band) taken by the Hinode Solar Optical Telescope with the hard X-rays observed by the Reuven Ramaty High Energy Solar Spectroscopic Imager. The two sets of data show closely similar ribbon structures, strongly suggesting that the flare emissions in white light and in hard X-rays have physically linked emission mechanisms. While the source structure along the ribbons is resolved at both wavelengths (length ∼ 30''), only the G-band observations resolve the width of the ribbon, with values between ∼0.''5 and ∼1.''8. The unresolved hard X-ray observations reveal an even narrower ribbon in hard X-rays (the main footpoint has a width perpendicular to the ribbon of <1.''1 compared to the G-band width of ∼1.''8) suggesting that the hard X-ray emission comes from the sharp leading edge of the G-band ribbon. Applying the thick-target beam model, the derived energy deposition rate is >5 x 1012 erg s-1 cm-2 provided by an electron flux of 1 x 1020 electrons s-1 cm-2 above 18 keV. This requires that the beam density of electrons above 18 keV be at least 1 x 1010 cm-3. Even if field lines converge toward the chromospheric footpoints, the required beam in the corona has too high a density to be described as a dilute tail population on top of a Maxwellian core. We discuss this issue and others associated with this extreme event, which poses serious questions to the standard thick target beam interpretation of solar flares.
[en] For several years we have explored the use of hard x-rays for a broad range of lithographic applications. The high energy available from the NSLS x-ray ring (E>15 keV) allows the exposure of resist up to several cm thick, while maintaining micron level precision. The high flux and close proximity to the source at this machine make it possible to achieve workable exposures on realistic time scales, enabling production work. In addition to the conventional two-dimensional exposure schemes, we have demonstrated methods for achieving fully figured three dimensional objects with internal re-entrant geometry. Users from outside BNL have been sufficiently successful with their work at our prototype beamline (X-27B) that we have initiated the construction of a dedicated exposure station (X-14B) for High Aspect Ratio Precision Manufacture. An overview of our previous work as well as the current status of the new beamline will be described. copyright 1997 American Institute of Physics
[en] In 1996, the idea of using compound refractive lenses for focusing hard X-rays was presented. An adiabatic lens is a kind of short-focal X-ray compound refractive lenses. An adiabatic lens consists of lenses with variable radius. As a kind of the adiabatic lens the adiabatic microcapillary lens is proposed. The microcapillary X-ray lens is developed as a row of bubbles in the shaped glass capillaries. Each bubble has a refractive surface for X-rays. The shape of the capillary defines the radius of the bubbles or refractive surfaces. Compound refractive surfaces define the optical properties of the adiabatic microcapillary lens. Spectral distributions of the focal spot of the adiabatic microcapillary lens are calculated. The possibilities of using the adiabatic microcapillary lens a X-ray filter are discussed. (authors)