A spectroscopic observation of emitted radiation from spray droplets, to measure the radiation mostly covering the visible region but extending to both near ultraviolet and infrared, was made along the plasma/spray flow from just the downsteam of a gun exit to a position where substrates are usually placed. The results revealed that although plasma radiation from some molecular and atomic lines are superimposed on a continuum background radiation at a position close to the gun exit, these lines almost completely disappear at a distance of more than 50 mm from the gun exit. In addition, the continuum radiation is well represented by the Planck's formula with the same fitted temperature of 2,750 ± 50 K at all positions. Finally, the wavelength dependencies of the surface emissivity of the droplets, ϵ(λ), lower the fitted temperatures by about 300 and 500 K, as one adopts the wavelength dependencies of ϵ(λ) ∝ λ-1 and λ-2, respectively.
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