Temperature dependence of the time delay to the onset of film boiling in liquid helium

We report measurements of the time delay to the onset of film boiling at the interface of a superheated solid and liquid helium I in the bath temperature range from 2.2 to 4.2 K. Our temperature dependent results suggest that delay times, t/sub d/, in the millisecond range are related to the applied heat flux, Q/sub app/, by the equation: Q/sub app/ = (α/t/sub d/) /sup 1/2//rho/1h/sub 1v/, where α(T) is the thermal diffusivity, /rho/1 is the liquid density, and h/sub 1v/ (T) is the latent heat of vaporization of liquid helium. The origin of this equation is discussed as well as its physical meaning in terms of describing the conditions necessary for the development of a film boiling configuration