For more than 25 years, the Physikalisch‐Technische Bundesanstalt has been strongly
engaged in the field of metrology using synchrotron radiation. In Berlin, this research …

As is known from visible-light experiments, silicon under femtosecond pulse irradiation can
undergo so-called “nonthermal melting” if the density of electrons excited from the valence to …

Time-resolved soft-x-ray photoemission spectroscopy is used to simultaneously measure the
ultrafast dynamics of core-level spectral functions and excited states upon excitation of …

We present measurements of second-and higher-order intensity correlation functions (so-
called Hanbury Brown—Twiss experiment) performed at the free-electron laser (FEL) …

In this contribution we review in detail our recently developed hybrid model able to trace
simultaneously nonequilibrium electron kinetics, evolution of an electronic structure, and …

It is shown that two radio frequency deflecting cavities with slightly different frequencies can
be used to produce time-dependent orbit deflection to a few special electron bunches …

The 5 p two-photon ionization cross section of xenon in the photon-energy range below the
one-photon ionization threshold is calculated within the time-dependent configuration …

Technique of undulator tapering in the post-saturation regime is used at the existing x-ray
FELs for increasing the radiation power. There are also discussions on the future of high …

We present a detailed theoretical study on the photoionization from the bound excited 1 P
state of He to continua dominated by multiple doubly excited resonance series embedded in …

We report on the results of the first operation of a frequency doubler at FLASH2. The scheme
uses the feature of the variable gap of the undulator. Undulator is divided in two parts. The …