“…For example, we have shown that a combination of neutron scattering, ion-beam scattering, and X-ray reflectivity experiments can elucidate detailed pore information, such as porosity and the average pore size. 2,3 The applicability of this methodology is, however, limited because neutron scattering is not a laboratory-scale facility. Attractive alternatives for measuring pore sizes in thin films include the positron beam techniques (lifetime spectroscopy and Doppler broadening measurements) that are especially useful for characterizing the very smallest pores (i.e., 2-20 Å in diameter).…”