Parameterization of fission barrier heights of medium, heavy and super heavy nuclei

Manjunatha, H. C.

doi:10.1007/s12648-017-1135-7

Cited by 18 publications

(6 citation statements)

References 30 publications

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“…Though QF timescale measured by the nuclear techniques using the mass-angle distribution [8,9,12,19], the neutron-clock method [10,18] and the giant dipole resonances [11] is in good agreement with the theoretical predictions [21][22][23][24][25][26][27][28][29][30][31], but it being at least two orders of magnitude lower than the values of the order of 10 −18 s as measured by the atomic techniques using the crystal blocking [14][15][16][17] and x-ray fluorescence [13,20]. The very long fission times can only be possible if the fission barriers of the isotopes involved in the decay chain are high, however theoretical estimates do not support it [32,33]. Further, recently a study [34] shows that short timescale 10 −20 s from nuclear techniques and long timescale from atomic techniques can only be reconciled by an extreme bimodal fission time distribution comprising a 53% longlived component (up to 10 −16 s) and a 47% short-lived component (up to 10 −21 s), provided the neutron emission from the accelerating fragments are ignored.…”

supporting

confidence: 54%

“…For example, 238 U bombarded on 197 Au at 24.3 MeV/u [40,41]. The CF is inevitable during the crystal blocking experiments in particular when the actinides are used in the reactions [14,17] because of low fission barrier of the actinides 6 MeV [32,33]. Even CF cannot be escaped for partners having high fission barrier used in the blocking experiment [15,16], e.g., tungsten (≈ 22 MeV).…”

mentioning

confidence: 99%

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On the timescale of quasi fission and Coulomb fission

Nandi¹,

Manjunatha²,

Gupta³

et al. 2021

Preprint

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Coulomb fission mechanism may take place if the maximum Coulomb-excitation energy transfer in a reaction exceeds the fission barrier of either the projectile or target. This condition is satisfied by all the reactions used for the earlier blocking measurements except one reaction 208 Pb + Natural Ge crystal, where the measured timescale was below the measuring limit of the blocking measurements < 1 as. Hence, inclusion of the Coulomb fission in the data analysis of the blocking experiments leads us to interpret that the measured time longer than a few attoseconds (about 2-2.5 as) is nothing but belonging to the Coulomb fission timescale and shorter than 1 as are due to the quasifission. Consequently, this finding resolves the critical discrepancies between the fission timescale measurements using the nuclear and blocking techniques. This, in turn, validates the fact that the quasifission timescale is indeed of the order of zeptoseconds in accordance with the nuclear experiments and theories. It thus provides a radical input in understanding the reaction mechanism for heavy element formation via fusion evaporation processes.

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supporting

confidence: 54%

mentioning

confidence: 99%

On the timescale of quasi fission and Coulomb fission

Nandi¹,

Manjunatha²,

Gupta³

et al. 2021

Preprint

Self Cite

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“…So, it seems that the description of the fission barrier top by two touching or separated fragments is not incompatible with the experimental fission barrier heights. It is worth mentioning the tentative to reproduce the fission barrier heights by analytical formulas [52] in the region 50 ≤ Z ≤ 130. Table 4: Comparison of the experimental [1,4,10,38,39,43] fission barrier heights E exp (in MeV) with the heights E th obtained in the prefered decay channels determined from the GLDM assuming the two-sphere approximation and the heights E th,def obtained when the deformation and microscopic effects of the fragments are taken into account.…”

Section: Fission Barriermentioning

confidence: 99%

Fusion and fission barrier heights and positions within the Generalized Liquid Drop Model

2021

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“…Here B f is the fission barrier and it is evaluated as the sum of the liquid drop barrier B f (LDM) and shell correction term (δU ). In the present study, we have evaluated the fission barriers using the semi-relation available in [65] for the heavy and superheavy regions.…”

Section: Spontaneous Fissionmentioning

confidence: 99%

Decay of dinuclear systems formed from dubnium

et al. 2021

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The radioactivity of the superheavy nuclei 250−275 Db is studied and presented using the Coulomb and proximity potentials. The half-lives corresponding to different decay modes such as α, cluster decay ( 12 C, 14 N, 18,20 O, 23 F, 20 Ne, 34 S, 28 Mg and 40 Ca) and spontaneous fission in the superheavy nuclei 250−275 Db are studied. The studied half-lives are compared with the available experiments. The decay modes and the branching ratios of isotopes of dubnium are presented. The isotopes of dubnium, 254−263 Db, are identified as α emitters, whereas isotopes such as 250−253 Db and 264−275 Db are identified as having spontaneous fission. The identified alpha emitting isotopes of dubnium have decay energies from 6 MeV to 10 MeV and half-lives 1 ms to 100 s. The possible projectile-target combinations to synthesise the superheavy nuclei 253−263 Db were predicted. The fusion of spherical projectile and target yields larger evaporation residue cross-sections.

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Parameterization of fission barrier heights of medium, heavy and super heavy nuclei

Cited by 18 publications

References 30 publications

On the timescale of quasi fission and Coulomb fission

On the timescale of quasi fission and Coulomb fission

Fusion and fission barrier heights and positions within the Generalized Liquid Drop Model

Decay of dinuclear systems formed from dubnium

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