Mass and charge distributions in the very asymmetric thermal neutron induced fission of the odd-Z nucleus 242mAm

Tsekhanovich, I.; Denschlag, H. O.; Davi, M.; Büyükmumcu, Zeki; Wöstheinrich, M.; Gönnenwein, F.; Oberstedt, S.; Faust, H.

doi:10.1016/s0375-9474(99)00338-3

Cited by 21 publications

(9 citation statements)

References 18 publications

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“…The results in the first three rows (panels from (b) to (g)) are based on the second, third and fourth finite differences, applied either directly to the yields (Y-2DI, Y-3DI and Y-4DI in the left columns), or to their logarithms (LY-2DI, LY-3DI and LY-4DI in the right columns). The results in the last two rows (panels 5 Similar absolute uncertainties occur also in presence of staggering and cannot be overlooked: for ∆Z = 0.1 they correspond to an uncertainty of ≈ ± 40% (20%) for Nc=200 (1000). …”

Section: Resultssupporting

confidence: 53%

“…The staggering effect was first investigated long time ago in the fission of actinide nuclei, mainly induced by low-energy neutrons (see e.g. [1,2,3,4,5,6,7,8] and references therein) and it was attributed to the extra energy required to break a pair of protons or neutrons [9]. Experimentally the odd-even effect in fission was found to be less pronounced for neutrons than for protons.…”

Section: Introductionmentioning

confidence: 99%

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Methods for a quantitative evaluation of odd-even staggering effects

Olmi¹,

Piantelli²

2015

Eur. Phys. J. A

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Abstract. Odd-even effects, also known as staggering effects, are a common feature observed in the yield distributions of fragments produced in different types of nuclear reactions. We review old methods, and we propose new ones, for a quantitative estimation of these effects as a function of proton or neutron number of the reaction products. All methods are compared on the basis of Monte Carlo simulations. We find that some are not well suited for the task, the most reliable ones being those based either on a non-linear fit with a properly oscillating function or on a third (or fourth) finite difference approach. In any case, high statistic is of paramount importance to avoid that spurious structures appear just because of statistical fluctuations in the data and of strong correlations among the yields of neighboring fragments.

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Section: Resultssupporting

confidence: 53%

Section: Introductionmentioning

confidence: 99%

Methods for a quantitative evaluation of odd-even staggering effects

Olmi¹,

Piantelli²

2015

Eur. Phys. J. A

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“…In the heavier part of the fragment distribution, the even-odd staggering was found to be negative, revealing a higher probability for the unpaired nucleon to end up in the heavy fragment. The same observation of large even-odd effect has been reported in thermal-neutron induced fission of 237 Np [13], and 242m Am [14]. The observation of an even-odd staggering for odd-Z fissioning nuclei reveals that the relation between the amplitude of the even-odd staggering in fission-fragment charge yields and the intrinsic excitation energy at scission is not as direct as depicted in the standard understanding as discussed above.…”

Section: -P2supporting

confidence: 71%

Influence of asymmetry and fissility on even-odd effect in fission-fragment yields

Caamaño

Rejmund

Schmidt

2010

EPJ Web of Conferences

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Abstract. Based on a wide systematics of fragment distributions measured in thermalneutron induced fission, the even-odd staggering in the fission-fragment element yields is investigated. The asymmetry evolution of the element yield distribution with the fissility of the fissioning nucleus is shown to be for an important part responsible for the decrease of the even-odd staggering with the fissility. The even-odd staggering close to symmetry is shown to be a small contribution to the global even-odd effect, and seems to vary little with the fissility of the nucleus. These experimental observations show that the established interpretation in which the intrinsic excitation energy at scission is accountable for the even-odd staggering amplitude has to be reconsidered.

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“…The best way to reduce its radiotoxicity is to transmute it either in thermal or fast reactors, which consequently leads to the fission of 242 Am. While yields are known for major actinides ( 235 U, 239 Pu) in thermal neutron-induced fission, only few measurements have been performed on 242 Am [1][2][3]. Moreover, the two main data libraries (JEFF-3.1.1 and ENDF/B-VII.0) do not agree among each other on the light peak.…”

Section: Motivationsmentioning

confidence: 99%

Measurement of mass yields from the²⁴¹Am(2n_th,f) reaction at the Lohengrin Spectrometer

Amouroux

Blanc

Bidaud

et al. 2013

EPJ Web of Conferences

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Abstract. The study of fission yields has a major impact on the characterization and understanding of the fission process and is mandatory for reactor applications. While the yields are known for the major actinides ( 235 U, 239 Pu) in the thermal neutron-induced fission, only few measurements have been performed on 242 Am. The interest of 242 Am concerns the reduction of radiotoxicity of 241 Am in nuclear wastes using transmutation reactions. This paper presents the measurement of the fission mass yields from the reaction 241 Am(2n th ,f) performed at the Lohengrin mass spectrometer (ILL, France) for both the light and the heavy peaks: a total of 41 mass yields have been measured. The experiment was also meant to determine whether there is a difference in mass yields between the isomeric state and the ground state as it exists in fission and capture cross sections. The method used to address this question is based on a repeated measurement of a set of fission mass yields as a function of the ratio between the 242g Am and the 242m Am fission rates. The presented experiment is also a first step towards the measurement of the isotopic fission yields of 242 Am .

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Mass and charge distributions in the very asymmetric thermal neutron induced fission of the odd-Z nucleus 242mAm

Cited by 21 publications

References 18 publications

Methods for a quantitative evaluation of odd-even staggering effects

Methods for a quantitative evaluation of odd-even staggering effects

Influence of asymmetry and fissility on even-odd effect in fission-fragment yields

Measurement of mass yields from the²⁴¹Am(2n_th,f) reaction at the Lohengrin Spectrometer

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Mass and charge distributions in the very asymmetric thermal neutron induced fission of the odd-Z nucleus 242mAm

Cited by 21 publications

References 18 publications

Methods for a quantitative evaluation of odd-even staggering effects

Methods for a quantitative evaluation of odd-even staggering effects

Influence of asymmetry and fissility on even-odd effect in fission-fragment yields

Measurement of mass yields from the241Am(2nth,f) reaction at the Lohengrin Spectrometer

Contact Info

Product

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About

Measurement of mass yields from the²⁴¹Am(2n_th,f) reaction at the Lohengrin Spectrometer