STUDY OF THE NEUTRON REACTIONS Li$sup 6$(n,/cap alpha/)H$sup 3$, F$sup 19$(n,$gamma$)F$sup 20$ AND I$sup 127$(n,$gamma$)I$sup 12$$sup 8$

The reactions Li/sup 6/(n, alpha )H/sup 3/, F/sup 19/(n, gamma )F/sup 20/ , and I/sup were studied using scintillating crystals both as targets and as detectors. The neutrons were produced by the termination of the Li/sup 7/(p,n)Be/ sup 7/ differential cross section was made in the proton energy range 1.9 to 3.0 Mev at 0 deg and the cross section observed at 2.27 Mev was 154 mb. Cross sections for this reaction were determined at 120 deg for proton energies below 2.4 Mev and at 60 deg for energies below 2.1 Mev. The Li/sup 6/(n, alpha )H/ sup 3/ reaction cross section was studied for neutron energies between 0.025 and 4 Mev. The resonance at 0.255 Mev wss observed to have a width (lab) of 0.125 Mev and a maximum cross section of 2.80 barns. A fit of the dispersion theory to this resonance yielded the following parameters in the center-of-mass coordinates: gamma /sub n/sup 2/ = 0.41 Mev-cm, gamma /sub alpha /sup 0.015 Mev-cm, DELTA /sub gamma = 0.17 Mev, E gamma = 0.039 Mev, and GAMMA = 0.188 Mev at the resonant energy. Sixteen resonances were observed in the F/sup 19/(n, gamma )F/sup 20/ reaction at neutron energiesmore » of 0.027, 0.04B, 0.100, 0.177, 0.270, twelve of these resonances vary between 1.1 and 8.6 ev. A monotonically decreasing cross section was observed for the I/sup 127/(n, gamma )I/sup 128/ reaction between 0.025 and 0.500 Mev. (auth)« less