Browsing by Subject "Uranium 235"

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Open Access
Influence of even nucleon numbers and closed shells on mass and charge distribution in low energy fission
(Kluwer Academic Publishers, 1994) Buyukmumcu, Z.; Erten, H. N.; Aras, N. K.
Extensive experimental and evaluated yield data are now available for the fragments in low energy nuclear fission. Using these data we re-examined the influence of even nuclear numbers and closed shells on the mass and charge distribution in low energy fission. We used WAHL's Zp model and Ap model. We also examined the effects of Z=50, N=82 and possibly N=88 shells. A new method was developed based on two Gaussian curves for the even and odd products. The EOZ and EON values calculated are based on these different methods and are seen to be consistent with each other in spite of the somewhat different definitions of the even-odd effect. The even-odd effect decreases with an increasing fissility parameter. The EON values are substantially lower than the corresponding EOZ values, probably due to the effect of washing out the neutron pairing effect by prompt neutron emission. The magnitude of the even-odd effect varies with different mass regions. The EOZ and EON values decrease as they go from asymmetric to symmetric regions in mass distributions. © 1994 Akadémiai Kiadó.
Open Access
Isomeric yields of130Sb, 132Sb, 134I, and 136I in the thermal neutron fission of235U
(Kluwer Academic Publishers, 1992) Erten, H. N.
Isomer yield ratios of130Sb,132Sb,134I and136I isomers formed in the thermal neutron fission of235U have been calculated from our previous experimental studies that led to the identification of these species. In those studies the iodine and antimony fractions formed in fission were rapidly separated and the decay of γ-rays belonging to each isomer pair were followed using Ge(Li) detectors and a multichannel analyzer. The isomer ratios were calculated from growth and decay considerations of these γ-rays. The results are compared with the recently published values obtained with an on-line isotope separator, those from LOHENGRIN, and those from model calculations. Angular momenta of fission fragments corresponding to the measured isomer yields have also been calculated.