THz SASE and seeded FEL based on high brightness photo injector PITZ

  • MP Department Seminar
  • Date: Apr 28, 2023
  • Time: 09:30 AM c.t. - 10:30 AM (Local Time Germany)
  • Speaker: Dr. Mikhail Krasilnikov
  • PITZ, Photo Injector Test Facility at DESY, Zeuthen
  • Location: Haber Villa
  • Room: Seminar Room
  • Host: Department of Molecular Physics
  • Contact:
THz SASE and seeded FEL based on high brightness photo injector PITZ

The Photo Injector Test Facility at DESY in Zeuthen (PITZ) develops a prototype of an accelerator-based high-power tunable THz source for pump-probe experiments at the European XFEL. The PITZ injector was originally built as a site for the development and preparation of the high-brightness electron source for the main linac of the European XFEL and has the same pulse train structure as the X-ray photon source of the XFEL. For the proof-of-principle experiments on high-power THz generation an LCLS- I undulator (on loan from SLAC) is installed in the tunnel annex downstream of the existing accelerator. A Self-Amplified Spontaneous Emission (SASE) FEL is used to generate the THz pulses. High radiation power can be achieved by utilizing high charge (up to several nC) electron bunches from the PITZ photo injector. A beam energy of ~17 MeV is used to generate narrowband THz radiation with a centre wavelength of 100 μm. The transport of this space charge dominated electron beam and its thorough matching into the planar LCLS-I undulator with a strong vertical focusing is one of the project challenges. The installation of the first THz beamline setup was finished in summer 2022 and commissioning with electron beam started. A specially developed procedure for a high charge beam matching into the undulator was successfully tested resulting in a first THz pulse generation. The start-up THz diagnostics is based on pyrodetectors (THz10). First measurements of the THz generation from 1 nC, 2 nC and 3 nC bunches have been taken, the statistics properties analysis corresponds to the expected SASE performance. Optimization of beam transport and matching resulted in the measurement of THz radiation with a pulse energy of tens of µJ, measured with pyroelectric detectors. The THz FEL gain curves were measured by means of specially designed short coils along the undulator. A brief overview of the PITZ facility, the results of the THz SASE FEL radiation characterization, as well as the first THz FEL seeding experiments at PITZ will be presented.

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