The Test-FEL at MAX-lab: Implementation of the HHG Source and First Results

The test-FEL at MAX-lab is a development set-up for seeding techniques. After the successful demonstration of coherent harmonic generation from a conventional laser, the new layout now presents a gas target for generation of harmonics. The drive laser will be up-converted and the low harmonics (around 100nm) will seed the electron beam. The energy modulated electrons will then be bunchedin thedispersivesection andwill radiateinthe second undulator. We will detect the second harmonic of the HHG radiation around 50nm. This experiment has several challenges never tried before: co-propagation of the electron beam and the drive laser, interaction of the electron beam with the gas in the target, no-focusingof the harmonics and no drive laser removal. The commissioning will show if this kind of in-line chamber has advantages with respect to more traditional approaches with optical beam transport. The results are relevant for many facilities that are planning to implement HHG seeding in the near future.