Coherent neutron scattering lengths and free cross sections were measured in order to determine the spin dependent scattering lengths of the isotopes of Li and B. The transmission measurements on Li at neutron energies of 0.51 meV, 1.26 eV and 5.19 eV delivered data for the eLi-abundances in the samples and for the free scattering cross section of 7Li. By means of experiments on 15 different samples of lithium compounds we obtained the complex spin state scattering lengths for the bound atoms to be: A review on slow neutron scattering and resonance data shows an over all consistency of all values.

Measurements of Neutron-Scattering-Amplitudes using the Christiansen-Filter- Technique By means of Christiansen-Filters it is possible to make use of the high accuracy achieved for the scattering amplitudes of liquids also for solids in form of powders. We investigated the scattering law for the small angle scattering of Neutrons by Christiansen-Filters and found a good agreement between theory and experiment. Using powders of several elements we could measure the scattering amplitudes of the elements with an uncertainty within ± 0.2% to ± 1%. We got for the bound atoms of Al: a = (3.449±0.009) F; Nb: a = (7.11 ± 0.04 ) F; Cr: a = (3.532 ± 0.010) F; Te: a= (5.43 ± 0.04 ) F; Sb: a = (5.641 ± 0.012) F; and Ta: a = (6.91 ± 0.07) F. Si: a = (4.159±0.006) F;

Coherent neutron scattering lengths and total cross sections were measured on elemental Ga, Ga-compounds and on isotopically enriched samples at neutron energies from 0.5meV up to 143keV using different techniques. From the experimental data the following quantities could be obtained: -the coherent scattering length of Ga and the spin state scattering lengths of the isotopes, -the potential scattering radii (R'), -the absorption cross sections of Ga, 69Ga, 71Ga and 75As.As derived quantities are given the coherent and incoherent cross sections and the resonance spin scattering lengths for the J=l and J=2 states of 7~ and 72Ga. The physical meaning of these data and of R' and the comparison with the resonance parameters are considered.

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Neutron scattering lengths and free scattering cross sections were measured for isolated isotopes and natural elements in the mass region from A = 12 to A = 27. By means of the Christiansen filter technique values for the coherent scattering lengths were obtained for the bound atoms of ~2C, 13C, ~4N, 15N, 260, 170, a80, Mg and a9F. Transmission experiments with neutrons of 0.51meV, 1.26eV and 5.19eV yielded data for the free scattering cross sections of 19F, 23Na, Mg and 19F. From all these results and with previous data the fundamental spin state scattering lengths for the concerned light nuclei have been deduced. The comparison of these values with resonance parameters has shown that the resonance data are complete. Therefore, values for the potential scattering radii could be obtained and discussed.