Elsevier

Nuclear Physics A

Volume 334, Issue 2, 4 February 1980, Pages 327-335
Nuclear Physics A

Fission fragment energy correlation measurements for the sub-barrier (nth, f) of 241Am and 243Am

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Abstract

Fission-fragment mass and kinetic-energy distributions and their correlations have been studied for the sub-barrier fission of the odd-odd 242Am and 244Am nuclei resulting from thermal neutron capture in 241Am and 243Am. Unwanted events were eliminated by a coherence test based on the time of flight. The 243Am mass distribution is more asymmetric and shows structures at μH ≈ 139 and 144, compared with that for 241Am which is smooth and structureless. The structure at μH ≈ 144 is caused by deformed neutron shells at N ≈ 88 in the heavy fragment and N ≧ 60 in the light fragment. While the 〈EK〉 at symmetry for 241Am is ≈ 19 MeV higher than that for 235U, it is shifted upwards only ≈ 6.5–10 MeV in the other mass regions. However, 〈EK〉 at symmetry for 243Am is ≈ 6 MeV lower than for 241Am and this decrease tapers down to ≈ 1 MeV for μH > 135. These data show a decrease in the total fragment deformation for 241Am at symmetry as predicted by calculations. However, the 243Am data show a sudden change back to higher deformation.

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Cited by (18)

  • Charge distribution of light mass fission products in the fast neutron induced fission of <sup>237</sup>Np, <sup>241</sup>Am and <sup>243</sup>Am

    2022, Applied Radiation and Isotopes
    Citation Excerpt :

    Thus it is quite interesting to carry out the studies on the kinetic energy, mass and charge distribution in the neutron induced fission of odd-Z actinides. From EXFOR compilation (IAEA-EXFOR Database Version of 2020-01-28 ; Otsuka et al., 2014), it was found that the kinetic energy and mass yield distribution in the neutron induced fission of 237Np (Naqvi et al., 1986; Hambsch et al., 2000; Pica et al., 2020), 241Am (Asghar et., 1980; Drapchinsky, 2004) and 243Am (Asghar et., 1980; Drapchinsky, 2004) have been carried out by using on-line measurements of fission products using coincidence technique or recoil mass separator. The charge distribution in the 237Np(2nth,f) (i.e. 238Np(nth,f)) and 241Am(2nth,f) (i.e. 242Am(nth,f)) reactions for the light mass fission products have been carried out by using recoil mass separator (Martinez et al., 1990; Davi et al., 1997; Tsekhanovich et al., 1999; Stumpf et al., 1992; Stumpf et al., 1995).

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At present at CEC Joint Research Centre, 21020-Ispra, Italy.

††

Centre d'Etudes Nucléaires de Bordeaux-Gradignan, Université de Bordeaux, France.

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