Author: Ewald, F.
Paper Title Page
WEAL1 Large Aperture X-ray Monitors for Beam Profile Diagnostics 608
  • C.A. Thomas, G. Rehm
    Diamond, Oxfordshire, United Kingdom
  • F. Ewald
    ESRF, Grenoble, France
  • J.W. Flanagan
    KEK, Ibaraki, Japan
  Emittance is one of the main characteristic properties of a beam of particles in an accelerator, and it is measured generally by means of the particle beam profile. In particular, when the beam of particles is emitting an X-ray photon beam, a non perturbative way of measuring the particle beam profile is to image it using the emitted X-ray photon beam. Over the years, numerous X-ray imaging methods have been developed, fulfilling the requirements imposed by a particle beam becoming smaller, and approaching micron size for electron beam machine with vertical emittance of the order of 1pm-rad. In this paper, we will first recall the properties of the X-ray photon as function of source and its properties. From this we will derive some natural definition of a large aperture X-ray imaging system. We will then use this selection criterion to select a number of X-ray imaging devices used as a beam profile diagnostics in an attempt to give an overview of what has been achieved and what is possible to achieve with the selected devices.  
slides icon Slides WEAL1 [7.499 MB]  
WEPF11 Emittance Measurement Using X-Ray Lenses at the ESRF 833
  • F. Ewald, J.C. Biasci, L. Farvacque, K.B. Scheidt
    ESRF, Grenoble, France
  During the year 2011, X-ray lenses were tested as an alternative way of emittance measurement in the ESRF storage ring. Following these tests it was decided to install a new bending magnet diagnostics beam port dedicated primarily to a permanent emittance measurement using X-ray lens imaging. The new beam port is equipped with a thin (0.6 mm) double CVD diamond window instead of 3 mm aluminium used at the pinhole beam ports. This increases the X-ray transmission, especially at low energies. The imaging and emittance measurement using aluminium lenses is discussed in comparison to the emittance measurement based on pinhole imaging. Although the principle works correctly, the setup presents different practical difficulties, such as low signal intensity and heat load.  
WEPF12 Characterisation of Al-Compound Refractive Lenses for X-Rays 837
  • F. Ewald, J.C. Biasci
    ESRF, Grenoble, France
  We report on measurements of the surface quality (shape) of aluminium compound refractive lenses using a thin collimated X-ray beam from one of our bending magnet diagnostics beam ports. Two types of lenses were tested for overall radius of curvature, surface quality and thickness: commercially available lenses (RWTH Aachen), and lenses of the same type manufactured at the ESRF. The different surface qualities can be readily discerned with our relatively simple setup. While the technique should be improved for more precise results, it already shows clearly the imperfect surface structure of the ESRF lenses. The image quality of the beam, however, is not affected to a visible extent in our emittance measurement setup at vertical emittances of typically ~ 6 pm.