Design and Commissioning of an Ionization Intensity Monitor

Sammanfattning: The dynamics of molecules and electrons takes place on timescales of femtoseconds and attoseconds, respectively. This requires ultrashort and intense extreme ultraviolet (XUV) pulses to be able to study them. Two sources that can generate intense XUV pulses are free-electron lasers (FELs) based on self amplified spontaneous emission (SASE) and high-order harmonic generation (HHG)driven by intense infrared (IR) laser. At the Lund attosecond science centre (LASC) the intense XUV beamline generates XUV pulses via HHG. To accomplish ultrashort and intense XUV pulses it is essential to have methods for alignment and photon flux diagnostics. In this work I have designed an ionization intensity monitor (IIM) and integrated it in the intense XUV beamline at LASC, with the purpose of measuring the photon flux of the generated XUV pulses. The design of the IIM is inspired by gas monitor detectors (GMDs) currently used at the soft X-ray FEL in Hamburg (FLASH) [1]. The working principle of the IIM is based on photoionization of rare gases and during commissioning it was shown that the IIM is sufficiently sensitive to XUV pulses to obtain both an ion and an electron signal. Performed single shot measurements determine the correlation between travel time of charge carriers and induced potential. By varying the energy of the generating IR pulses we investigate the linearity between the number of generated electrons and the photon flux of the XUV pulses.