July 2011 Archives

An innovative X-ray camera, designed to record bursts of images at an unprecedented speed of 4.5million frames per second, is being built with the help of the UK's Science and Technology Facilities Council (STFC) and will be delivered to the European XFEL (X-ray Free-Electron Laser) in 2012. For further information, visit the Web page, http://www.stfc.ac.uk/About%20STFC/36221.aspx

Parametric down-conversion is a quantum-optical process in which a 'pump' photon splits spontaneously into two (the 'signal' and 'idler') in a nonlinear optical medium. Recently, Professor T. Ishikawa (RIKEN, Harima, Japan) and his colleagues reported their experiments with X-ray photons. They have visualized three-dimensionally the local optical response of diamond at wavelengths between 103 and 206 Å with a resolution as fine as 0.54 Å. This corresponds to a resolution from λ/190 to λ/380, an order of magnitude that is the best ever achieved. For more information, see the paper, "Visualizing the local optical response to extreme-ultraviolet radiation with a resolution of λ/380", K. Tamasaku et al., Nature Physics 7, 705 (2011).

So far, because of the difficulty of creating a target of neutral atomic nitrogen, there have been no reports on the details of high-resolution K-edge spectra. Recently, scientists at Lawrence Berkeley National Laboratory have performed both experimental and theoretical studies on the strong 1s→np resonance features throughout the threshold region. The absolute value of the K-shell binding energy was experimentally obtained for the first time, and it was 409.64±0.02 eV. For more information, see the paper, "K-Shell X-Ray Spectroscopy of Atomic Nitrogen", M. M. Sant'Anna et al., Phys. Rev. Lett. 107, 033001 (2011).