The reaction238U +238U at 7.42MeV/u

The yields of over 200 projectile-like fragments (PLFs) and target-like fragments (TLFs) from the interaction of (E c.m. =450 MeV) 136 Xe with a thick target of 208 Pb were measured using Gammasphere and off-line γ-ray spectroscopy, giving a comprehensive picture of the production cross sections in this reaction.The measured yields were compared to predictions of the GRAZING model and the predictions of Zagrebaev and Greiner using a quantitative metric, the theory evaluation factor, tef. The GRAZING model predictions are adequate for describing the yields of nuclei near the target or projectile but grossly underestimate the yields of all other products. The predictions of Zagrebaev and Greiner correctly describe the magnitude and maxima of the observed TLF transfer cross sections for a wide range of transfers (∆Z = -8 to ∆Z = +2). However for ∆Z =+4, the observed position of the maximum in the distribution is four neutrons richer than the predicted maximum. The predicted yields of the neutron-rich N=126 nuclei exceed the measured values by two orders of magnitude. Correlations between TLF and PLF yields are discussed.

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“…These reactions were extensively studied experimentally in the 1980s [3][4][5][6][7][8]. (An in-depth review of these data is found in [9].)…”

Section: Introductionmentioning

confidence: 99%

Xe136+Pb208reaction: A test of models of multinucleon transfer reactions

et al. 2015

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“…Experimental results supporting the above described hypotheses can be found in [3]. In this experiment [3], inclusive one particle measurements were performed for the charge, the kinetic energy and the angular distributions of the reaction products from 238 U+ 238 U at 7.42A MeV. Relatively large mass transfers have been found for deep inelastic reactions with the largest Q-values.…”

Section: Decay Channelsmentioning

confidence: 64%

“…it will be very difficult to isolate it from quasielastic or deep inelastic processes. Experimental results supporting the above described hypotheses can be found in [3]. In this experiment [3], inclusive one particle measurements were performed for the charge, the kinetic energy and the angular distributions of the reaction products from 238 U+ 238 U at 7.42A MeV.…”

Section: Decay Channelsmentioning

confidence: 66%

“…239 U, where a pronounced double bump is observed, related to the doubly magic nucleus 132 Sn. The idea that 208 Pb may play an important role in fission of transuranium nuclei was raised frequently, and is partially experimentally proven [2,3,4,1,5]. In order to check this idea for this extremely heavy system, we performed a statistical calculation in a micro-canonical approach that treats fission and light particle emission in the same manner [6,7].…”

Section: Decay Channelsmentioning

confidence: 99%

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Search for a long lived component in the reaction U+U near the Coulomb barrier

Villari

Golabek

Mittig

et al. 2007

AIP Conference Proceedings

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Abstract. We performed an experiment to search for a signature of a long living component in the collision of 238 U + 238 U between 6.09 and 7.35A MeV. The experiment was performed at GANIL using the spectrometer VAMOS, tuned for observing reactions with kinematics similar to fusionfission events. Theoretical calculations indicate that if a long living component would exist for this reaction, the most probable fission channel of such a giant system would be via the emission of quasi-lead nuclei. We detected events of such a category in the focal plane of VAMOS. These events present an excitation function growing as a function of the bombarding energy.

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“…These reactions were studied extensively about thirty years ago. Among other topics, there had been great interest in the use of heavy-ion transfer reactions to produce new nuclear species in the transactinide region [17][18][19][20][21][22]. The cross sections were found to decrease very rapidly with increasing atomic number of surviving heavy fragments.…”

Section: Transfer Reactionsmentioning

confidence: 99%

Synthesis of superheavy nuclei: Obstacles and opportunities

Zagrebaev

Карпов

Greiner

2015

EPJ Web of Conferences

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Abstract. There are only 3 methods for the production of heavy and superheavy (SH) nuclei, namely, fusion reactions, a sequence of neutron capture and beta(-) decay and multinucleon transfer reactions. Low values of the fusion cross sections and very short half-lives of nuclei with Z>120 put obstacles in synthesis of new elements. At the same time, an important area of SH isotopes located between those produced in the cold and hot fusion reactions remains unstudied yet. This gap could be filled in fusion reactions of 48 Ca with available lighter isotopes of Pu, Am, and Cm. New neutron-enriched isotopes of SH elements may be produced with the use of a 48 Ca beam if a 250 Cm target would be prepared. In this case we get a real chance to reach the island of stability owing to a possible beta(+) decay of 291 114 and 287 112 nuclei formed in this reaction with a cross section of about 0.8 pb. A macroscopic amount of the long-living SH nuclei located at the island of stability may be produced by using the pulsed nuclear reactors of the next generation only if the neutron fluence per pulse will be increased by about three orders of magnitude. Multinucleon transfer processes look quite promising for the production and study of neutron-rich heavy nuclei located in upper part of the nuclear map not reachable by other reaction mechanisms. Reactions with actinide beams and targets are of special interest for synthesis of new neutron-enriched transfermium nuclei and not-yet-known nuclei with closed neutron shell N=126 having the largest impact on the astrophysical r-process. The estimated cross sections for the production of these nuclei allows one to plan such experiments at currently available accelerators. MotivationDue to the bending of the stability line toward the neutron axis, in fusion reactions of stable nuclei one may produce only proton rich isotopes of heavy elements. For elements with Z > 100 only neutron deficient isotopes (located to the left of the stability line) have been synthesized so far (see the left panel of Fig. 1). That is the main reason for the impossibility to reach the center of the "island of stability" (Z ∼ 110 ÷ 120 and N ∼ 184) in fusion reactions with stable projectiles. Further progress in the synthesis of new elements with Z > 118 is not quite evident. Cross sections of the "cold" fusion reactions decrease very fast with increasing charge of the projectile (they become less than 1 pb already for Z ≥ 112 [1, 2]). For the more asymmetric 48 Ca induced fusion reactions rather constant values (of a few picobarns) of the cross sections for the production of SH elements up to Z=118 were found [3]. This unusual (at first sight) behavior of the cross sections has been predicted and explained in [4,5] by the relatively slow decrease of the fusion probability (in contrast to the more symmetric "cold" fusion reactions) and by the increasing survival probability of compound nuclei (CN) owing to increasing values of their fission barriers caused by the larger shell corrections as the CN approach the ...

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The reaction238U +238U at 7.42MeV/u

Cited by 132 publications

References 23 publications

Xe136+Pb208reaction: A test of models of multinucleon transfer reactions

Xe136+Pb208reaction: A test of models of multinucleon transfer reactions

Search for a long lived component in the reaction U+U near the Coulomb barrier

Synthesis of superheavy nuclei: Obstacles and opportunities

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