A method for estimating the temperature in high energy density free electron laser experiments

摘要: Abstract Present and forthcoming free electron laser (FEL) large scale facilities deliver high fluence ultrafast soft hard X-ray pulses able to create probe warm dense matter (WDM). Proper diagnostic for basic physical quantities, like temperature density, is necessary, but the short lifetime of WDM state (few ps) makes their measurements a challenging task. In this work we propose method estimate using experimental information from slow pyrometric exploiting properties heat diffusion equation. Numerical simulations show that typical thin foil samples, measurement with 1 – 10 μ s temporal resolution at distance about 300 500 m beam center contains sufficient retrieve initial spatial distribution accuracy providing on reached in regime. The inversion obtained by means Bayesian approach Metropolis Monte Carlo numerical procedure. model calculations presented provide theoretical background development device diagnostics TIMEX end-station Fermi@Elettra FEL facility.