RESONANTLY ENHANCED NEUTRON INTENSITY IN A SURFACE SEGREGATED POLYMERBLEND

We have formed a resonant cavity for a massive particle, the neutron, in an attractive potential between a surface segregated polymer film a nd its substrate. Standing waves occur when incident waves interfere w ith the waves reflected from the substrate. Multiple internal reflecti ons lead to an enhanced intensity at resonant wave vectors below the w ave vector for total reflection. At these resonant wave vectors the en hanced neutron intensity incoherently scatters from the hydrogen conta ining polymer of the potential well causing a marked decrease in the r eflectivity. The position of the resonant dips provides an aid to fitt ing the reflectivity data by restricting the possible scattering lengt h density profiles. This phenomena may find application in the study o f in-plane correlations by enhancing off-specular scattering.