Systematics of nuclear charge distribution in fission the ZP model |
| |
Authors: | A C Wahl |
| |
Institution: | (1) Washington University, St. Louis, Missouri, (USA) |
| |
Abstract: | An extension of the conventional ZP model has been used with data for ten fission reactions and the method of least-squares for derivation of parameters that
describe the nuclear charge-distributions. Data for light and heavy fission products for each reaction were treated together
by consideration of the complementarity of average mass numbers of precursors (A′L+A′H=AF). This treatment gave calculated yields that are essentially equal for complementary elements (ZL+ZH=ZF). The parameters determined,
, the Gaussian dispersion width parameter, a linear function of ΔZ=|ZP-A′(ZF/AF)|, ZP being the Z at maximum of the curve, and
and
, the even-odd proton and neutron yield enhancement factors, represented most data (AH⋟130–150 and the complementary light A's) moderately well, better than did oscillating functions of
and ΔZ. The
values were found to be approximately constant (0.48 to 0.62) and, generally, to increase with the average number of neutrons
emitted,
. The ΔZ values at A′=140 were in the range of 0.42 to 0.50, and the slopes, ∂ΔZ/∂A′H, ranged from 0.0 to 0.03. The
factor was found to be several times larger than the
factor and to decrease with increasing excitation energy and with A and/or Z of the fissioning nucleus, as has been reported
previously. The adequacy of the ZP model for representation of data and for prediction of yields in the high-yield mass-number regions mentioned above are discussed,
and the large uncertainties that are involved in extrapolating the model to near symmetric or to very asymmetric mass and
charge divisions are pointed out. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|