On the evening of 4 October, the team in the control room at FLASH, the soft X-ray, free-electron laser facility at DESY, observed lasing at a wavelength of 7 nm for the first time. Just 24 hours later, the team achieved the design value of 6.5 nm. This comes two weeks after the facility had reached the design beam energy of 1 GeV.
Image credit: DESY.
In FLASH, superconducting modules accelerate electrons before they pass through an undulator. The aim is for the spontaneous radiation that they emit in the undulator to amplify itself to form free-electron laser radiation pulses. During the latest shutdown, researchers installed the sixth and final accelerator module and replaced another so that the operators could begin to take FLASH to its design energy for the first time.
On 21 September, the DESY team observed a peak around 6 nm in the wavelength spectrum of the spontaneous radiation generated in the undulator. This proved that all six accelerator modules were working as planned and accelerating the electron bunches to an energy of 1 GeV. Then, on 4 October the team observed the first laser pulses at 6.5 nm.
