Naik Haladhara, Dange Srikant Pandurang, Singh Ram Janam
Radiochemistry Division, Bhabha Atomic Research Centre, Mumbai, 400 085, India.
Radiochemistry Division, Bhabha Atomic Research Centre, Mumbai, 400 085, India.
Appl Radiat Isot. 2022 Apr;182:110137. doi: 10.1016/j.apradiso.2022.110137. Epub 2022 Feb 4.
Isobaric charge distribution has been carried out in the thermal neutron induced fission of U, U and Pu by measuring the fractional cumulative yields (FCY) of various heavy mass fission products within the range of 127-149. An off-line γ-ray spectrometric technique was used for the measurement of fission product activities. The width of the isobaric charge distribution (σ), most probable charge (Z) and thus the experimental charge polarization (ΔΖ) as a function of fragment mass were obtained. It was found that the σ values around the mass number 127-129 and 132-136 are lower due to the presence of spherical 50p and 82n shells. The ΔΖ values show an oscillating nature in the interval of five mass units due to even-odd effect. The ΔΖ values also show a decreasing trend with the approach of symmetric split besides an oscillating nature. The most probable charge (Z) and thus the ΔΖ values based on the minimum potential energy surface were theoretically calculated, which show a systematic decreasing trend with the approach of symmetric split due to the liquid drop behaviour of the fissioning nucleus.
通过测量127 - 149范围内各种重质量裂变产物的分数累积产额（FCY），对热中子诱发的U、U和Pu裂变进行了等压电荷分布研究。采用离线γ射线能谱技术测量裂变产物活度。得到了等压电荷分布宽度（σ）、最可几电荷（Z）以及作为碎片质量函数的实验电荷极化（ΔΖ）。结果发现，由于存在球形的50p和82n壳层，质量数在127 - 129和132 - 136附近的σ值较低。由于奇偶效应，ΔΖ值在五个质量单位的区间内呈现振荡性质。除了振荡性质外，随着对称分裂的临近，ΔΖ值也呈现下降趋势。基于最小势能面理论计算了最可几电荷（Z）以及相应的ΔΖ值，由于裂变核的液滴行为，随着对称分裂的临近，它们呈现出系统的下降趋势。
