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Tomar, B. S.; Goswami, A.; Das, S. K.; Srivastava, B.; Guin, R.; Sahakundu, S. M.; Prakash, Satya

doi:10.1103/physrevc.38.1787

Cited by 14 publications

(14 citation statements)

References 19 publications

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“…The angular momentum of fission products is considered to be determined by the following factors; the excitation energy and the spin of fissioning nucleus [14], the mass splitting [8], the charge distribution [ 11,15], the fragment kinetic energy [ 12], the atomic and neutron numbers or their closed shell effect [16,17], the internal excitation (or deformation) energy of fragments [12,13,18,19], and so on. Until now, it has been understood that the isomeric yield ratio is related to the angular momentum of primary fragment.…”

Section: Introductionmentioning

confidence: 99%

Isomeric yield ratios of fission products in the system of 24 MeV proton-induced fission of238U

Tanikawa

Kudo

Sunaoshi

et al. 1993

Z. Physik A - Hadrons and Nuclei

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Abstract. Isomeric yield ratios of 30 fission products in 24 MeV proton-induced fission of 23au were measured by the use of the ion-guide isotope separator on-line. The obtained isomeric yield ratios were converted to the angular momenta of primary fission fragments based on the statistical model. The deduced angular momenta were examined from various aspects. It is found that in general the angular momentum continuously increases with the fragment mass number including the region of symmetric mass division. However, there are some exceptions. For Sn isotopes the deduced angular momenta are quite small due to the spherical shape of the nuclear shell configuration. It is also concluded from the consideration of the charge distribution that the angular momentum of fission product scatters considerably within the narrow range of mass division. The dependence of the angular momentum on the available energy of fragments at scission point indicates that the individual fragment possesses a characteristic deformation at scission and/or the deduced angular momentum is seriously affected by the particle excitation after scission.

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Section: Introductionmentioning

confidence: 99%

Isomeric yield ratios of fission products in the system of 24 MeV proton-induced fission of238U

Tanikawa

Kudo

Sunaoshi

et al. 1993

Z. Physik A - Hadrons and Nuclei

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“…This is highlighted in Ref. [31] for the α-induced fission of 238 U, in Ref. [15] where the isomer ratios of fission fragments at high excitation energies were studied, and in Ref.…”

Section: Discussion On the Isomeric Yield Ratiosmentioning

confidence: 98%

“…According to the calculations performed with the GEF code, higher relative yield of the super long (SL) fission channel results in pronounced population of the high-spin isomer, hinting that the fission modes may affect the isomeric yield ratio. The importance of the excitation energy (E * ) of the compound nucleus on the isomeric yield ratios can be perceived in the following way: When a high amount of excitation energy is available, the initial spin of the fission fragments, and consequently the isomer production ratios, is expected to be higher due to the higher degree of freedom in collective motion [24,31]. Moreover, differences in the excitation energy will be reflected in differences in the de-excitation process.…”

Section: Discussion On the Isomeric Yield Ratiosmentioning

confidence: 99%

“…In addition, the experimentally determined yields of metastable states in fission are necessary for calculations of the effect of delayed neutrons in nuclear reactors, since the β-delayed neutron emission probability from the metastable state can be notably different from that of the ground state, as, for example, in the case of 98 Y [23]. Furthermore, from the experimental determination of the isomeric yield ratios [24][25][26][27][28][29][30][31], the angular momentum of the initial fission fragments can be deduced using statistical model analysis [6,32]. This method can be used for all fission products, both with odd and even Z, but typically requires nuclides with suitable half-lives.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

First isomeric yield ratio measurements by direct ion counting and implications for the angular momentum of the primary fission fragments

et al. 2018

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Publisher's PDF Rakopoulos, V.; Lantz, M.; Solders, A.; Al-Adili, A.; Mattera, A.; Canete, Laetitia; Eronen, Tommi; Gorelov, Dmitry; Jokinen, Ari; Kankainen, Anu; Kolhinen, Veli; Moore, Iain; Nesterenko, Dmitrii; Penttilä, Heikki; Pohjalainen, Ilkka; Rinta-Antila, Sami; Simutkin, V.; Vilén, Markus; Voss, Annika; Pomp, S.Rakopoulos, V., Lantz, M., Solders, A., Al-Adili, A., Mattera, A., Canete, L., . . . Pomp, S. (2018). First isomeric yield ratio measurements by direct ion counting and implications for the angular momentum of the primary fission fragments. Physical Review C, 98 (2) We report the first experimental determination of independent isomeric yield ratios using direct ion counting with a Penning trap, which offered such a high resolution in mass that isomeric states could be separated. The measurements were performed at the Ion Guide Isotope Separator On-Line (IGISOL) facility at the University of Jyväskylä. The isomer production ratios of 81 Moreover, based on the isomeric yield ratios, the root-mean-square angular momenta (J rms ) of the fission fragments after scission were estimated using the TALYS code. The experimentally determined isomeric yield ratios, and consequently the deduced J rms , for 130 Sn are significantly lower compared to 128 Sn for both fissioning systems. This can be attributed to the more spherical shape of the fragments that contribute to the formation of 130 Sn, due to their proximity to the N = 82 shell closure. The values of J rms for 129 Sb are higher than 128 Sn for both reactions, despite the same neutron number of both nuclides (N = 78), indicating the odd-Z effect where fission fragments with odd-Z number tend to bear larger angular momentum than even-Z fragments. The isomer production ratio for the isotopes of Sn is more enhanced in the nat U(p, f ) reaction than in 232 Th(p, f ). The opposite is observed for 96 Y and 97 Y. These discrepancies might be associated to different scission shapes of the fragments for the two fission reactions, indicating the impact that the different fission modes can have on the isomeric yield ratios.

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“…A similar effect was observed and interpreted in the literature, as a result of the strong influence of the spherical 82 neutron and deformed 66 neutron shells on the scission configuration. 21 We now suggest that the effect may be due to the increased contribution of the SL channel as we approach symmetric division from heavy fragment side. 22 Due to quite large uncertainties in the experimental results, a stronger conclusion cannot be put forward.…”

Section: Resultsmentioning

confidence: 99%

Possible exit channel effect on isomer yield ratios

Kildir

Morel

Büyükmumcu

et al. 1997

J Radioanal Nucl Chem

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Isomer yield ratio measurements in fission are important in understanding the fission process. With the development of new instrumental techniques, a large number of yield data are now available. The experimental data on isomer yield ratios in the thermal neutron induced fission of 235U are compared with those calculated from the simple statistical model by MADLAND and ENGLAND. The method of calculation has been extended to the isotopes having more than one isomeric stale. The results may be explained according to the multi-exit-channel model of fission.

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Fragment angular momenta in alpha-induced fission ofU238

Cited by 14 publications

References 19 publications

Isomeric yield ratios of fission products in the system of 24 MeV proton-induced fission of238U

Isomeric yield ratios of fission products in the system of 24 MeV proton-induced fission of238U

First isomeric yield ratio measurements by direct ion counting and implications for the angular momentum of the primary fission fragments

Possible exit channel effect on isomer yield ratios

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