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出版United States. Department of Energy, 2005
URLhttp://books.google.com.hk/books?id=oyyTAQAACAAJ&hl=&source=gbs_api
註釋A first demonstration has recently been made of radiography of implosions using a nonthermal K{alpha} radiation source generated with a high intensity picosecond laser pulse [1]. Absolute source brightness is important in assessing the potential of this diagnostic and we present here measurements and Monte-Carlo simulations of the brightness of the Ti K{alpha} back-lighter source. The experiment was conducted at the Vulcan laser within the Rutherford Appleton Laboratory (RAL) in the UK. A set of radiographs were taken in which a back-lighting source was produced using a 1 ps CPA beam. The beam delivered an average of 49J, within an 800 {micro}m by 400 {micro}m elliptical spot, onto a 25 {micro}m thick Ti foil (Figure 1). The first of two instruments used to characterize the K{alpha} source was a spherical Bragg crystal imager (Quartz 20{bar 2}3, 2d of 0.2749 nm, radius of curvature 38 cm, aperture 1.6 cm) used to spatially resolve the emission of the K{alpha} back-lighter [2]. The crystal focused the 4.5 keV K{alpha} photons with 10 mm spatial resolution and 7.9 x magnification onto a cooled, 16-bit, 1'' x 1'', 1024 x 1024 pixel CCD chip. The instrument observation angle was normal to the rear axis of the foil. The 2nd instrument was a single hit CCD spectrometer which was used to measure the absolute K{alpha} yield from the Ti target. The spectrometer consisted of a back-thinned CCD with 2048 x 2048 13.5 {micro}m square pixels and a filter (100 or 150 {micro}m Ti) that placed the chip in the single hit photon regime. The angle of observation was 41{sup o} from the rear surface normal of the Ti foil.