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Mordhorst, E.; Strecker, M.; Frobeen, H.; Gasthuber, Martin; Scobel, W.; Gebauer, B.; Hilscher, D.; Lehmann, M.; Rossner, H.; Wilpert, Th.

doi:10.1103/physrevc.43.716

Cited by 31 publications

(37 citation statements)

References 60 publications

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“…In many experimental studies on heavy systems it is commonly found that if the temperature of the compound nucleus T CN is raised, the temperature at scission point T SC remains almost constant [1,10,27]. This supports the picture in which fission occurs after that the composite nucleus has cooled down until has reached an excitation energy of roughly 50-60 MeV, independently on the excitation energy of the initial compound nucleus.…”

Section: How To Probe a Temperature-dependent Viscositysupporting

confidence: 54%

Fission Dynamics: The Quest of a Temperature Dependent Nuclear Viscosity

Vardaci

Nitto

Nadtochy

et al. 2013

JNP

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Abstract. This contribution presents a journey within the open questions about the current use of a temperature dependent nuclear viscosity in models of nuclear fission and proposes an alternative experimental approach by using systems of intermediate fissility. This study is particularly relevant because: i) systems of intermediate fissility offer a suitable framework since the intervals between the compound nucleus and scission point temperatures with increasing excitation energy are much smaller than in the case of heavier systems, ii) the measurement of observables in the ER channel translates into a larger set of effective constraints for the models.

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Section: How To Probe a Temperature-dependent Viscositysupporting

confidence: 54%

Fission Dynamics: The Quest of a Temperature Dependent Nuclear Viscosity

Vardaci

Nitto

Nadtochy

et al. 2013

JNP

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“…The recoil velocity V of the composite system parallel to the direction of the beam was determined from the measured folding angle and fragment velocities of each event, following the procedure given in Ref. [20]. The ratio V /V CN, where V CN is the composite system velocity for full momentum transfer, was obtained as a function of fragment-mass ratio m R .…”

Section: Discussionmentioning

confidence: 99%

Binary fragmentations of excited nuclear systems in the 372 MeVFe56+Th232reaction

Sahu¹,

Thomas²,

Saxena³

et al. 2005

Phys. Rev. C

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The binary fragmentation of the excited superheavy system of Z = 116 formed in the reaction 372 MeV 56 Fe + 232 Th has been investigated. The fragment masses and kinetic energies were determined through measurement of the fragment velocities by the time-of-flight method. Neutron spectra were measured in coincidence with the fragments at several angles with respect to the fragment direction, which were analyzed to deduce the total as well as the pre-scission neutron multiplicities. We analyzed the correlations between fragment mass and kinetic energy, gated and nongated by the coincidence with neutrons, to learn about the dynamics of the reaction with respect to the two-body exit channels. The events in the near-mass-symmetric valley region appear to receive a significant contribution from the asymmetric mode of fission of the superheavy compound nucleus Z = 116, which can be due to the influence of the closed proton and neutron shells of Z = 50 and N = 82 in the light fragments. From the observed number of pre-scission neutrons, it is inferred that the time scales of the fissionlike reactions leading to near-mass-symmetric splits are rather large, of the order of several times 10 −20 s. The average number of prompt neutrons emitted in the spontaneous fission of such a superheavy nucleus is ν = (12 ± 1), as deduced from the neutron measurements.

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“…It contained two position-sensitive low-pressure multiwire chambers MWC of active size 61 x 61 mm 2 and two surface barrier detectors F2, F3 (thickness 170 #m, active area 700 mm z) in fixed positions in a planar geometry. Distances, angles and solid angles are given in Table 1 [10] in symmetric binary fragmentations and covered the range from 40% to 100% LMT for such events. Coincident heavy fragments observed with each one MWC and F detector on opposite sides of the beam focus on asymmetric fragmentations following high LMT.…”

Section: Methodsmentioning

confidence: 99%

“…p = 0.4-1.0), on a determination of neutron multiplicities by two different methods that allow comparison with those of [10], and on a discussion of effects broadening the LMT and thus the O12 distribution. To faciliate a comparison with the 4~ results from [2,8] we shall convert the LMT into an E~N scale by means of the massive transfer model.…”

Section: Introductionmentioning

confidence: 98%

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Total neutron multiplicities as a measure of the violence in heavy ion reactions

Knoche

Sprute

Behrmann

et al. 1992

Z. Physik A - Hadrons and Nuclei

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Energy spectra and multiplicities of neutrons from the reaction system 838 MeV 32S projectiles on 197Au have been measured in coincidence with binary fragmentations. Neutron detection was performed simultaneously in a 4re scintillator sphere and by time-of-flight. The linear momentum transfer (LMT) and the excitation energy E~N are deduced with the folding angle technique. Neutron multiplicities are compared for consistency and discussed as a measure of LMT and E*N. The saturation of M4~(E*N) beyond E*N ~ 400 MeV seen for several systems of high fissility (x > 0.8) is attributed to the spreading of the folding angle distribution and the increasing competition of charged particle evaporation.

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Time scales for binary fragmentations of highly excited, fissile nuclei fromS32+

Cited by 31 publications

References 60 publications

Fission Dynamics: The Quest of a Temperature Dependent Nuclear Viscosity

Fission Dynamics: The Quest of a Temperature Dependent Nuclear Viscosity

Binary fragmentations of excited nuclear systems in the 372 MeVFe56+Th232reaction

Total neutron multiplicities as a measure of the violence in heavy ion reactions

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