Attosecond time delays in heavy-ion induced fission measured by crystal blocking

Andersen, J. U.; Chevallier, J.; Forster, J.S.; Karamian, S. A.; Vane, C. R.; Beene, J. R.; Galindo-Uribarri, A.; Campo, J. Gómez del; Gross, C. J.; Krause, H.; Padilla‐Rodal, E.; Radford, D. C.; Shapira, D.; Broude, C.; Malaguti, F.; Uguzzoni, A.

doi:10.1103/physrevc.78.064609

Cited by 35 publications

(21 citation statements)

References 39 publications

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“…The observation of blocking dips without narrowing from lifetime effects, with the same technique and apparatus as in Ref. [3], underpins the interpretation there of the narrower blocking dips observed for bombardment of a W target.…”

Section: Introductionsupporting

confidence: 53%

“…This paper describes the continuation of a series of experiments [1][2][3] on lifetimes of heavy-ion-induced fission using the crystal-blocking technique [4]. For fission of high-Z nuclei (Z = 90-106), we found the surprising result that the fission decay is characterized by a single lifetime of order 1 attosecond (as).…”

Section: Introductionmentioning

confidence: 94%

“…The physics of the fission process in the present experiment differs markedly from that of the high-Z nuclei studied in Refs. [1][2][3]. The basic description developed in the 1970s is based on the rotating-liquid-drop model (RLDM) [15].…”

Section: Introductionmentioning

confidence: 99%

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Time delays in heavy-ion-induced fission of medium-Znuclei, measured by crystal blocking

et al. 2012

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Time delays in fission induced by bombardment of Mo with 170-and 180-MeV 32 S, 225-and 240-MeV 48 Ti, and 300-MeV 58 Ni have been measured by observation of crystal blocking of fission fragments. In contrast to earlier measurements with a W target, the results are consistent with fission of a compound nucleus in competition with mainly neutron emission. Most of the fissions happen on a time scale much shorter than attoseconds but there is a significant component of fission with much longer lifetimes. The measurements are reproduced with a standard statistical model, including a Kramers correction to fission widths from the viscosity of hot nuclear matter. These new results support the interpretation of our earlier measurements with a W target, which indicate that there is a transition in heavy-ion-induced fission at large atomic number and mass, from multichance fission in the standard Bohr-Wheeler picture to fission without formation of a compound nucleus. The process is slowed down by nuclear viscosity, with measured delays of order attoseconds.

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Section: Introductionsupporting

confidence: 53%

Section: Introductionmentioning

confidence: 94%

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Time delays in heavy-ion-induced fission of medium-Znuclei, measured by crystal blocking

et al. 2012

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“…Experimental methods to obtain quantitative timescales [71] for fission reactions include pre-scission neutron multiplicities [72][73][74], crystal blocking [75,76], and observation of compound nucleus X-rays [77]. Each has problems when faced with measuring the short quasifission timescales [77,78].…”

Section: -P9mentioning

confidence: 99%

Nuclear Reaction Dynamics Research at the Australian National University

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Dasgupta

Carter

et al. 2013

EPJ Web of Conferences

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“…This is because of its importance for understanding experimental data involving fusion-fission, fusion-evaporation and quasifission processes [1][2][3][4][5][6] as well as because of its relevance to the synthesis of superheavy nuclei [7,8]. Due to dissipation, fission is delayed.…”

Section: Introductionmentioning

confidence: 99%

Significant role of deformation in probing postsaddle nuclear dissipation with light particle emission

2010

Phys. Rev. C

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Using a one-dimensional Langevin model, we study the effects of deformation on the multiplicities of postsaddle neutrons, protons, α particles, and giant dipole resonance (GDR) γ rays of a heavy fissioning system 240 Cf as probes of postsaddle nuclear dissipation (β). It is shown that postsaddle dissipation effects on these light particles have a significant deformation dependence. Furthermore, we find that the role of deformation depends on the type of the particle. It reduces the sensitive influence of β on protons, α particles, and GDR γ rays substantially, whereas it enhances the sensitivity of neutrons to β. The results suggest that to accurately extract the postsaddle friction strength by comparing measured prescission particle multiplicities of heavy nuclei with calculations based on statistical models or stochastic equations like Langevin equations, it is important to take into account the deformation effects. The influence of model dimensionality is discussed.

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Attosecond time delays in heavy-ion induced fission measured by crystal blocking

Cited by 35 publications

References 39 publications

Time delays in heavy-ion-induced fission of medium-Znuclei, measured by crystal blocking

Time delays in heavy-ion-induced fission of medium-Znuclei, measured by crystal blocking

Nuclear Reaction Dynamics Research at the Australian National University

Significant role of deformation in probing postsaddle nuclear dissipation with light particle emission

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