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• Introduction Introduction • Fission in the r-process Fission in the r-process • (n,f)- and (n,f)- and -delayed fission-delayed fission• fission cyclingfission cycling• Contribution different fission modesContribution different fission modes• sf sf – predictions – predictions • Superheavy nuclei and cosmochronometersSuperheavy nuclei and cosmochronometers• ConclusionConclusion
Spontaneous fission of heavy nuclei and nucleosynthesis of cosmo-chronometers in the r-
process. Panov Igor
(ITEP)
fission
2. R-process under high neutron density environment – in NSM
Observed Nr
fissionfission
decaydecay
PPkn (k=0,1,2,3)
Network calculations of the r-processNetwork calculations of the r-process
(n,) (n)
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Nuclear data for the r-process (up to 6000 nuclei )
• beta-decay,
•Cross-sections and reaction rates (n,g), (n,f), ..
• beta-delayed processes Pin, Pdf
• spontaneous fission, sf
•Mass distribution of fission products•Alpha-decay, •Nuclear masses and fission barriersData base of common usage
JINA - Joint Institute of Nuclear AstrophysicsJINA - Joint Institute of Nuclear Astrophysics
• Seeger, Fowler, et al. (1965) ; Ohnishi (1977) • Thielemann, Metzinger, Klapdor, Zt.Phys., A309 (1983) 301. Pdf=100%• Goriely et al. Astron. Astrophys. 346, 798–804 (1999) s.f. (Swiatecky)• Panov et al., Nucl. Phys. A, 718 (2003) 647. (n,fission) vs Pdf
• I.Korneev et al. NIC-2006; Astronomy Letters, 66 (2008) 131 Yff(Z,A)• Kelic, et al., Phys. Lett. B. 616 (2005) 48 Yff(Z,A)• I.V. Panov, E. Kolbe, F.-K. Thielemann, T. Rauscher, B. Pfeiffer, K.-L. Kratz.
NP A 747 (2005) 633 (n,fission) (n,) Pdf
• G.Martinec-Pinedo et al, Progress in Particle and Nuclear Physics, 59 (2007) 199. (n,fission) vs Pdf
• Y.-Z. Qian, Astron. J. 569 (2002), p. L103. induced fission
• Kolbe, Langanke, Fuller. Phys Rev Lett. 2004 induced fission • I. Petermann et. al. NIC-2008; G.Martinec-Pinedo et al, Progr. in Particle
and Nucl. Phys., 59 (2007) 199-205: (n,fission), Pdf , s.f., induced f..• Panov et al. AA 2010Panov et al. AA 2010 (n,fission) and (n,) • Petermann Martinec-Pinedo Langanke Panov Thielemann SHE AA2012• Panov, I.Korneev, Yu. Lutostansky, F.-K. Thielemann. Yad.Fiz. 2013. Pdi
3. fission in the r-process and rates fission in the r-process and rates calculationscalculations
4. Fission cycling during r-process for NSM conditions 4. Fission cycling during r-process for NSM conditions (t-duration time of the r-process; t=0 - initial composition)(t-duration time of the r-process; t=0 - initial composition)
Neutron star mergers modelling: Rosswog et al. 1999R-process: Panov I., Thielemann F.-K. AL, 30 (2004) 711
4. Fission cycling – fission fragments are involved in the r-process as new seeds
I.Petermann, A.Arcones, A.Keli´c, K.Langanke, G.Martínez-Pinedo, W.Schmidt, K-H.Hix, I. Panov, T. Rauscher, F.-K. Thielemann, N.Zinner, NIC-2008;
5.
R=∫i(t) / ∑i ∫ i(t)dt
6. Spontaneous fission 6. Spontaneous fission ratesrates
• Lg(sf ) ~ Bf (Frankel&Metropolis,1947) :
Lg(sf ) = 33,3-7,77Bf(exp) (1)
Lg(sf ) =50,127-10,145Bf(etfsi) (2)
Panov, Korneev, G. Martinez-Pinedo, Thielemann, 2013
• LgLg((sf sf ) = ) = --11461146,,4 + 754 + 75,,33ZZ22//A A –– 11,,638(638(ZZ22//AA))22 + + 00,,012(012(ZZ22//AA))33 --(7(7,,24 24 --00,,095095ZZ22//AA))BBf f (3)(3)
Zagrebaev, Karpov 2012 (Zagrebaev, Karpov 2012 (Swiatecki, 1957))
• Macro-micro model, Smolanchuk et al. 1997Macro-micro model, Smolanchuk et al. 1997 (4)
Bf ETFSI- Mamdouh et al., NP 2001
R-process path and abundances YA(Z,N) when duration r ~ 10s
nn < 1022 cm-3, n < Squares – most abundant nucleiWhite dots: 10% < Pdf < 90%
A(progenitors) ~ < 260
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nn < 1012, n <<
JINR => Zagrebaev et al. Phys. Rev. C 84, 044617 (2011)
Amax(progenitors) ≈280
Final abundance YA when s.f. rates ~
f(Bf)
Final YA when s.f.rates - macro-micro model
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ConclusionsConclusions• Spontaneous fission model strongly influe Spontaneous fission model strongly influe
upon the r-process nucleosynthesis upon the r-process nucleosynthesis yields of nuclei-cosmochronometersyields of nuclei-cosmochronometers
• Among tested models of spontaneous fission Among tested models of spontaneous fission phenomenological model based on phenomenological model based on Swiatecki model and on macro-micro model Swiatecki model and on macro-micro model predictions gave the better results in predictions gave the better results in calculation of yields of nuclei–calculation of yields of nuclei–cosmochronometerscosmochronometers
• Additionally to 232/235, 235/238 pairs of Additionally to 232/235, 235/238 pairs of nuclei-cosmochronometers, pairs 232/244 or nuclei-cosmochronometers, pairs 232/244 or 238/244 can be considered238/244 can be considered
• The detailed investigation of decay chain is The detailed investigation of decay chain is neededneeded
Thank youThank you !!
• everybody for attention and everybody for attention and collaborationcollaboration
• SNF for supportSNF for support
Final abundances YFinal abundances YA , R ~ 0.4 – 4 109 years