The working principle of the intensity monitors is the atomic photo-ionization of a rare gas at low particle density in the range of 1011 cm-3 (p ≈ 10-5 mbar). The photon beam traveling through a rare gas-filled chamber generates ions and electrons, which are extracted and collected separately. From the currents generated this way it is possible to derive the absolute number of photons per pulse, shot by shot. The I0Ms have the following characteristics:
  • almost completely transparent
  • wide dynamical range 
  • no saturation effects 
  • independent from the beam position fluctuations
  • usable on the whole wavelength of FERMI
  • usable continuously for on-line shot-to-shot measurements
  • provide the absolute number of photons per single pulse

Last Updated on Friday, 15 November 2019 12:07