Photofission of235U and238U at intermediate energies: absolute cross sections and fragment mass distributions

Frommhold, Th.; Steiper, F.; Henkel, W.; Kneißl, U.; Ahrens, J.; Beck, R.; Peise, J.; Schmitz, M.; Anthony, I.; Kellie, J. D.; Hall, S.J.; Miller, G.J.

doi:10.1007/bf01289589

Cited by 44 publications

(4 citation statements)

References 34 publications

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“…Following up this pioneering work, photon absorption on nuclei has been measured at the Mainz Microton (MAMI) facility [296,297] with a beam energy of E γ = 0.05-0.8 GeV, with higher energies of E γ = 0.2-1.2 GeV at the Adone storage ring facility (Frascati, Italy) [298,299,300,301,302], using the SAPHIR tagged photon beam of E γ = 0.5-2.67 GeV at ELSA (Bonn, Germany) [303] and at Hall B of the Jefferson Laboratory (Newport News, USA) [304,305] with a beam energy of E γ = 0.17-3.84 GeV. In fact, some of the above experiments have not measured directly the photoabsorption cross section but only the photofission cross section [296,297,300,298,304,305]. Contrary to earlier assumptions, it has been shown by Cetina et al [304,305] that these two cross sections need not be identical.…”

Section: Total Photoabsorption Cross Sectionmentioning

confidence: 99%

Transport-theoretical description of nuclear reactions

et al. 2012

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In this review we first outline the basics of transport theory and its recent generalization to offshell transport. We then present in some detail the main ingredients of any transport method using in particular the Giessen Boltzmann-Uehling-Uhlenbeck (GiBUU) implementation of this theory as an example. We discuss the potentials used, the ground state initialization and the collision term, including the in-medium modifications of the latter. The central part of this review covers applications of GiBUU to a wide class of reactions, starting from pion-induced reactions over proton and antiproton reactions on nuclei to heavy-ion collisions (up to about 30 AGeV). A major part concerns also the description of photon-, electron-and neutrino-induced reactions (in the energy range from a few 100 MeV to a few 100 GeV). For this wide class of reactions GiBUU gives an excellent description with the same physics input and the same code being used. We argue that GiBUU is an indispensable tool for any investigation of nuclear reactions in which final-state interactions play a role. Studies of pion-nucleus interactions, nuclear fragmentation, heavy-ion reactions, hypernucleus formation, hadronization, color transparency, electronnucleus collisions and neutrino-nucleus interactions are all possible applications of GiBUU and are discussed in this article.

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Section: Total Photoabsorption Cross Sectionmentioning

confidence: 99%

Transport-theoretical description of nuclear reactions

et al. 2012

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“…The resulting selfenergy expressions are similar to equation (3) but with only the scattering part (k 0 < 0) retained (note that this is consistent with our description of the (1232) in vacuum where πB loops are not included). [29]) and nuclei (right panel; data from [30][31][32][33][34][35]).…”

Section: Self-energies At Finite Temperature and Densitymentioning

confidence: 99%

“…Figure2. Photoabsorption cross sections on nucleons (left panel, data from[29]) and nuclei (right panel; data from[30][31][32][33][34][35]). …”

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The Δ(1232) at RHIC

Hees

Rapp

2005

J. Phys. G: Nucl. Part. Phys.

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Abstract. We investigate properties of the ∆(1232) and nucleon spectral functions at finite temperature and baryon density within a hadronic model. The medium modifications of the ∆ consist of a renormalization of its pion-nucleon cloud and resonant π∆ scattering. Underlying coupling constants and form factors are determined by the elastic πN scattering phase shift in the isobar channel, as well as empirical partial decay widths of excited baryon resonances. For cold nuclear matter the model provides reasonable agreement with photoabsorption data on nuclei in the ∆-resonance region. In hot hadronic matter typical for late stages of central Au-Au collisions at RHIC we find the ∆-spectral function to be broadened by ∼65 MeV together with a slight upward mass shift of 5-10 MeV, in qualitative agreement with preliminary data from the STAR collaboration.

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“…Experimental results obtained at Frascati [9,10], Mainz [12,13], Bonn [1,14], Saskatoon [15], and Thomas Jefferson Laboratory [16,17] have shown, however, that this was not the case. The fissility for thorium and several uranium isotopes was found to be lower than that for neptunium, showing that nuclear fissility does not saturate for those nuclei, remaining at a value below 100% even at high incident photon energies.…”

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Photofission and total photoabsorption cross sections in the energy range of shadowing effects

et al. 2006

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The energy dependence of photofission cross section for heavy nuclei has recently been well described in terms of a Monte Carlo calculation at energies from the pion photoproduction threshold up to 1 GeV [see, for instance, A. Deppman et al., Phys. Rev. Lett. 87 (2001) 182701]. Recent experimental data from CLAS (CEBAF Large Angle Spectrometer) collaboration have extended the measured photofission cross section up to 3.5 GeV for actinide and preactinide nuclei. In this work we address the calculation of photoabsorption and photofission cross sections for actinide and preactinide nuclei above 1 GeV, a region where the shadowing effect plays an important role in the nuclear photoabsorption process. DOI: 10.1103/PhysRevC.73.064607 PACS number(s): 25.20.−x, 25.85.Jg, 24.10.Lx, 24.85.+p Photon-nucleus reactions are excellent tools for investigating nuclear and nucleonic structures. The photonuclear absorption process, for instance, has been used to study the formation and propagation of baryonic resonances inside nuclear matter [1-6], the photon hadronization process that gives rise to the shadowing effect in the photoabsorption cross section [1,7], or the formation and propagation of hyperons in the nucleus [6]. The simplicity of photonuclear reactions as compared to reactions induced by other probes, from both the theoretical and experimental points of view, is attractive to those willing to study nuclear and subnuclear structures.However, the various nuclear processes taking place during the reaction, mainly at intermediate and high energies, cause some problems in the comprehension of the nuclear or subnuclear mechanisms. One example is the fissility of heavy nuclei. It was supposed that fissility was an increasing function of the photon energy, and that for actinide nuclei, which present the highest fissility values among the stable nuclei, one could expect their fissility to be 1 for energies above a few hundred MeV [8]. In fact, the measurement of fission cross section was proposed as a reliable method for measuring the total photoabsorption cross section [9,10]. A fine, although incomplete, overview on the theoretical approaches for calculating photofission cross sections is presented in Ref. [11].Experimental results obtained at Frascati [9,10], Mainz [12,13], Bonn [1,14], Saskatoon [15], and Thomas Jefferson Laboratory [16,17] have shown, however, that this was not the case. The fissility for thorium and several uranium isotopes was found to be lower than that for neptunium, showing that nuclear fissility does not saturate for those nuclei, remaining at a value below 100% even at high incident photon energies. This result was fully explained by a Monte Carlo study of the intranuclear cascade and evaporation/fission competition processes that follows the photon absorption, as implemented by the MCMC and MCEF codes [18,19]. The important feature for explaining the nonsaturation of the heavy-nuclei fissility was the inclusion of protons and α-particles evaporation in the evaporation-fission competition proc...

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Photofission of235U and238U at intermediate energies: absolute cross sections and fragment mass distributions

Cited by 44 publications

References 34 publications

Transport-theoretical description of nuclear reactions

Transport-theoretical description of nuclear reactions

The Δ(1232) at RHIC

Photofission and total photoabsorption cross sections in the energy range of shadowing effects

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