Observation of resonance enhanced neutron standing waves through (n, α) reaction

The neutron resonances in the (LiF)-Li-6(200 Angstrom)/Ti(2000 Angstrom) /Cu(1000 Angstrom)/glass layered structure have been observed simultaneously by neutron reflectivity and Li-6(n, alpha) H-3 nuclear reaction, A ionization chamber was used to register the alpha and triton particles emitted after the neutron capture in Li-6 nuclei. The observation of the neutron density resonant character in the spacer needs a neutron absorber layer which. for the present experiment, was the cap layer itself. For definite wavelengths one looks for minima on the reflectivity curve which corresponds to maxima on the cc-spectra and H-3-spectra. The charged particle normalized intensity reflects the resonant behavior of neutron density in the cap layer Li-6 which is st result of the realization of the resonances in the spacer layer (Ti). The decreasing of the enhancement factor with the increasing of the resonance order is directly seen on both registration channels. Fitting of charged particles and neutron data helps significantly in characterizing the depth profile of the sample and leads to the idea that the Ti spacer layer could be used as a medium far sensitive investigation. (C) 2000 Elsevier Science B.V. All rights reserved.