Beamline Description

DiProI Beamline layout

The DiProI end-station and the dedicated beamline that transports and tailors the FEL pulses for meeting the stringent requirements of coherent scattering experiments were commissioned in 2011-2012, a detailed description is available in Capotondi et al. Review of Scientific Instruments, 84 051301 (2013). Exploiting the advantage of FERMI seeded FEL, the same Ti:sapphire IR laser, that triggers the FEL emission, can also be used as a source for IR pulses that are delivered to the end-station through a dedicated IR ‘beamline’ and two optical breadboards. These IR pulses are intrinsically synchronized with the FEL and can be used as either pump or probe in almost jitter-free time resolved experiments. Hereafter we will briefly describe the core capabilities of the FEL and IR beamlines: more detailed information can be found in Zangrando et al. Review of Scientific Instruments, 80 113110 (2009), Raimondi et al. Nuclear Instruments and Methods in Physics Research A, 710 131 (2013), Cinquegrana et al. Physical Review Special Topics - Accelerators and Beams, 17 040702 (2014), Danailov et al. Optics Express, 22 12869 (2014).
Layout of the DiProI beamline

PADReS, the FERMI-FEL Photon transport

The Photon Analysis, Delivery and Reduction System (PADReS) consists of several units that secure full control of the FEL beam. The beamlines have a common initial part and can be alternatively fed by the FEL-1 and FEL-2 pulses (spectral range 4-100 nm in the first harmonic), inserting a switching mirror. The shot-to-shot intensity of the FEL radiation is recorded and can be attenuated by more than three orders of magnitude using a gas cell, endowed with a couple of independent upstream and downstream I0 monitors. Additional attenuation of the FEL intensity and/or suppression of the seeding UV radiation is attained by inserting different solid state filters (Al, Zr, Pd), placed along the beamline. An online spectrometer provides single shot information about the spectral quality of the FEL radiation.   32.5 nm pulses observed at 10 Hz on a YAG:Ce A split-and-delay device can split the FEL beam into two parts using the edge of a grazing-incidence mirror and subsequently recombine them on the same optical axis after their travel on adjustable length paths. The generated relative delay is ranging from -2 ps up to 30 ps and is used for FEL pump-FEL probe experiments. To increase the pulse energy densities to several J/cm2, required for investigation of very small objects in a single-shot mode, an active optical system based on two bendable mirrors in  Kirkpatrick-Baez (KB) configuration is positioned before the DiProI station.

Last Updated on Wednesday, 16 October 2019 12:13