Generation of ultrashort $Kα$ radiation from quasipoint interaction area of femtosecond pulses with thin foils

We demonstrate a concept for short x-ray generation at $1kHz$ repetition rate from a thin-foil target in a very compact configuration, which allows one, essentially, to decrease the distance between x-ray source and investigated object. The scaling for the hard x-ray yield and the hot electron temperature with the pulse intensity are determined and best described by a power law. The useful photon fluxes of $3.4×109$ and $3.3×109phot∕(ssrad)$ are generated for the Ni- and Cu $Kα$ lines, respectively. The size of the x-ray source was detected to be $10μm$⁠.