The goal of experiments carried out at GSI with high intensity laser system PHELIX is the investigation of mechanisms leading to effective production of photons with energies above 20 keV required for monochromatic backlighting of Warm Dense Matter (WDM). In experiments, 1ω, 500fs, 100J laser pulses were used for irradiation of 3 mm thick Ag targets and thin foils deposited on Al and plastic substrates. The laser intensity was varied between 10 and 4 × 10 W/cm by changing the laser focal spot size. In this report we present a comparison of numerical simulations of the silver Kα-photon yield with experimental results obtained by means of a single-hit CCD technique [1]. In simulations, the Kα-photon yields from Ag foils in given direction into a unit of solid angle per laser pulse energy, Nk, were calculated according to the model [2], which takes into account dependencies of the conversion efficiency of laser energy into hot electrons η(IL) [1] and average energy of hot electrons Th(IL) [3] on the laser pulse intensity IL(r, t), as well as a self-absorption of 22.1 keV Kα photons in a foil of arbitrary thickness. In the case of Gaussian laser pulse, IL(υ) = I0 exp(−υ), υ = r/r 0 + t /t0, we get