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Title:	Alpha preformation probability for even-even alpha-decay superheavy nuclei with Z=108-118 using cluster formation model
Authors:	Alsaif Norah Ahmed M (P67183)
Supervisor:	Shahidan Radiman, Prof. Dr.
Keywords:	Microscopy Alpha decay Universiti Kebangsaan Malaysia -- Dissertations Dissertations, Academic -- Malaysia
Issue Date:	30-Jan-2018
Description:	Most microscopic models which have been used for estimation of the preformation probability, appear to be too complicated for application to superheavy nuclei due to the complexity of the nuclear many-body problem. But, the recently successful determination of the preformation probability through the cluster formation model (CFM) for even-even heavy nuclei motivates us to present a study to determine the preformation probability values for the six even-even superheavy isotopes (Hs, Ds,Cn, Fl, Lv and Un) with atomic number Z=108-118 and neutron numbers 144 ≤ N ≤ 200 in the mass region from 252 to 318. The CFM formula, which has been used for the calculation of the preformation probability, depends on the alpha-cluster formation energy and the total energy of the surface nucleons in the parent nucleus. These energies are determined from the differences in the binding energies of nuclei. The masses of the nuclei were taken from the Koura, Tachibana, Uno, and Yamada (KTUY) mass formula. Thus, the preformation probability of each nucleus is calculated individually. The accurate and realistic preformation probability values are found to be in good agreement with the previous theoretical results of heavy and superheavy nuclei. In addition, the results showed a good consistency with the alpha-decay constants. Therefore, the findings clearly showed that the CFM remains valid for superheavy nuclei. In addition, our calculations reveal that the alpha clustering mechanism and the formation probability in even-even superheavy nuclei are similar to those of even-even heavy nuclei in a general sense. Furthermore, the preformation probability, the formation energy and the total energy were discussed and explained in detail according to the different shell regions around the magic and submagic numbers. The dramatic change of the preformation probability, the formation energy and the total energy with respect to neutron numbers reflects some properties of their nuclear structure. Hence, the prediction of magic nucleus occurs at N=172, 184 and Z=114, indicating a new Island for the cluster radioactivity around the superheavy isotope 286114 and 298114 as double-shell closure nuclei. One of the more significant findings to emerge from this study is that the important role of the shell effects on alpha clustering. This study is an extension as well as a test of validity for the CFM, which offers a convenient approach to determine the preformation probability of other wide range for superheavy nuclei. Therefore, we presume that the present realistic preformation probability values of the wide range of superheavy isotopes will be a guide to more accurate calculations of the half -live and other properties., 'Certification of Master's/Doctoral Thesis' is not available,Ph.D.
Pages:	95
Call Number:	QH205.2.A376 2018 tesis
Publisher:	UKM, Bangi
Appears in Collections:	Faculty of Science and Technology / Fakulti Sains dan Teknologi

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