Scattering of low-energy helium atoms from a low-temperature solid surface

The first measurements are presented of the scattering of low-energy (2 meV) He atoms from a solid surface at low temperature (Ts=3.6 K). The results are consistent with calculations which assume that all incident atoms either stick with probability or are scattered elastically and specularly. As the mean incident angle with respect to the surface normal decreases from 45°to 14°, increases from 0.77 to 0.94.