Measurements of the xenon density in a pulsed jet from absorption of monochromatic soft X-rays

The density distribution in a pulsed xenon gas jet emanating through cylindrical and conic (supersonic) nozzles in vacuum was investigated experimentally and theoretically for different stagnation pressures and at different instants of time. The measurements were made from absorption of monochromatic soft X-rays (SXRs) (λ = 13.6 nm) produced by a nanosecond laser-plasma source. Focusing normal-incidence multilayer mirrors were employed for the monochromatisation of soft X-rays and the production of transmission jet images (X-ray absorption patterns). Numerical simulations were made of the transient outflow of xenon in vacuum taking cluster production into account. The measured absolute density values and the density distribution agree nicely with the simulations.