High resolution measurements of mass, energy and nuclear charge correlations for 229Th(nth, f) with the cosi fan tutte spectrometer

Abstract The COSI FAN TUTTE spectrometer has been used to measure for the first time in one go the mass-charge-energy correlations for well-resolved light group masses for 229 Th(n th , f). About 4.8 × 10 5 events were collected in a ≈ 3 months run. The global mass distribution shows structures and the distribution for E L = (112±0.5) MeV is dominated by mass numbers A L = 86 and 96. The mean kinetic energy 〈E L 〉 shows strong fluctuations as a function of the light fragment mass A L . The mean proton odd-even effects in yields and energy are д p = (40.0±1.0)% and д E o-e TKE = (1.35±0.17) MeV , respectively. The δ p(E L ) varies by a factor of ≈ 3 for E L = 02 to 107 MeV with a plateau for E tL ≈ 96 to 103 MeV. The mean neutron odd-even effect is δ n = (1.95±0.5)%). The mean value of the conditional variance is 〈σ 2 ( Z ¦ A )〉 = (0.33±0.02) and it varies little with energy. The conditional variance seems to decrease as one goes from 252 Cf to 230 Th. These data are discussed in the context of existing results on other nuclei.