Fission decay of 48Cr at E*CN≈60 MeV

K. A. Farrar, S. J. Sanders, A. K. Dummer, A. T. Hasan, F. W. Prosser, B. B. Back, I. G. Bearden, R. R. Betts, M. P. Carpenter, B. Crowell, M. Freer, D. J. Henderson, R. V F Janssens, T. L. Khoo, T. Lauritsen, Yun Liang, D. Nisius, A. H. Wuosmaa, C. Beck, R. M. Freeman & 2 others Sl Cavallaro, A. Szanto De Toledo

Research output: Contribution to journalArticle

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Abstract

The fully energy-damped yields for the 36Ar + 12C and 20Ne + 28Si reactions at Ec.m. = 47.0 MeV and 45.5 MeV, respectively, are explored using particle-particle-γ coincidence data. These reactions reach a similar excitation energy of E*CN= 59.5 MeV in the 48Cr compound nucleus as was obtained in an earlier particle-particle coincidence study of the 24Mg + 24Mg reaction. The overall mass and total kinetic energy distributions of the fission fragments are found to be well reproduced by statistical-model calculations. These calculations are also found to reproduce structure seen in the excitation-energy spectra for the 20Ne + 28Si and 24Mg + 24Mg exit channels for all three reactions. In previous excitation-function measurements, strong heavy-ion resonance behavior has been observed in elastic and inelastic cross sections for the 24Mg - 24Mg system. There has been speculation that peaks observed in the corresponding excitation-energy spectra at more negative Q values may also be a consequence of this resonance phenomenon. The observation of very similar behavior with the asymmetric-mass entrance channels makes it less likely, though, that the peaks arise from any special configuration of the compound system. Instead, an analysis of the γ-ray data and the results of statistical-model calculations support the conclusion that most of the observed high-lying structure can be accounted for in terms of statistical fission from a fully energy- and shape-equilibrated compound nucleus. For the 24Mg + 24Mg entrance channel, however, comparisons with the statistical model indicate a reduction of high-angular-momentum partial cross sections, leading to the 24Mg + 24Mg fission channel. For the first time, we are able to deduce the nature of the competition between the resonance and statistical-fission mechanisms in this mass region.

Original languageEnglish (US)
Pages (from-to)1249-1261
Number of pages13
JournalPhysical Review C
Volume54
Issue number3
DOIs
StatePublished - Sep 1996
Externally publishedYes

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fission
decay
entrances
excitation
energy spectra
nuclei
cross sections
energy
rays
heavy ions
energy distribution
angular momentum
kinetic energy
fragments
configurations

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Nuclear and High Energy Physics

Cite this

Farrar, K. A., Sanders, S. J., Dummer, A. K., Hasan, A. T., Prosser, F. W., Back, B. B., ... Szanto De Toledo, A. (1996). Fission decay of 48Cr at E*CN≈60 MeV. Physical Review C, 54(3), 1249-1261. https://doi.org/10.1103/PhysRevC.54.1249

Fission decay of 48Cr at E*CN≈60 MeV. / Farrar, K. A.; Sanders, S. J.; Dummer, A. K.; Hasan, A. T.; Prosser, F. W.; Back, B. B.; Bearden, I. G.; Betts, R. R.; Carpenter, M. P.; Crowell, B.; Freer, M.; Henderson, D. J.; Janssens, R. V F; Khoo, T. L.; Lauritsen, T.; Liang, Yun; Nisius, D.; Wuosmaa, A. H.; Beck, C.; Freeman, R. M.; Cavallaro, Sl; Szanto De Toledo, A.

In: Physical Review C, Vol. 54, No. 3, 09.1996, p. 1249-1261.

Research output: Contribution to journalArticle

Farrar, KA, Sanders, SJ, Dummer, AK, Hasan, AT, Prosser, FW, Back, BB, Bearden, IG, Betts, RR, Carpenter, MP, Crowell, B, Freer, M, Henderson, DJ, Janssens, RVF, Khoo, TL, Lauritsen, T, Liang, Y, Nisius, D, Wuosmaa, AH, Beck, C, Freeman, RM, Cavallaro, S & Szanto De Toledo, A 1996, 'Fission decay of 48Cr at E*CN≈60 MeV', Physical Review C, vol. 54, no. 3, pp. 1249-1261. https://doi.org/10.1103/PhysRevC.54.1249
Farrar KA, Sanders SJ, Dummer AK, Hasan AT, Prosser FW, Back BB et al. Fission decay of 48Cr at E*CN≈60 MeV. Physical Review C. 1996 Sep;54(3):1249-1261. https://doi.org/10.1103/PhysRevC.54.1249
Farrar, K. A. ; Sanders, S. J. ; Dummer, A. K. ; Hasan, A. T. ; Prosser, F. W. ; Back, B. B. ; Bearden, I. G. ; Betts, R. R. ; Carpenter, M. P. ; Crowell, B. ; Freer, M. ; Henderson, D. J. ; Janssens, R. V F ; Khoo, T. L. ; Lauritsen, T. ; Liang, Yun ; Nisius, D. ; Wuosmaa, A. H. ; Beck, C. ; Freeman, R. M. ; Cavallaro, Sl ; Szanto De Toledo, A. / Fission decay of 48Cr at E*CN≈60 MeV. In: Physical Review C. 1996 ; Vol. 54, No. 3. pp. 1249-1261.
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title = "Fission decay of 48Cr at E*CN≈60 MeV",
abstract = "The fully energy-damped yields for the 36Ar + 12C and 20Ne + 28Si reactions at Ec.m. = 47.0 MeV and 45.5 MeV, respectively, are explored using particle-particle-γ coincidence data. These reactions reach a similar excitation energy of E*CN= 59.5 MeV in the 48Cr compound nucleus as was obtained in an earlier particle-particle coincidence study of the 24Mg + 24Mg reaction. The overall mass and total kinetic energy distributions of the fission fragments are found to be well reproduced by statistical-model calculations. These calculations are also found to reproduce structure seen in the excitation-energy spectra for the 20Ne + 28Si and 24Mg + 24Mg exit channels for all three reactions. In previous excitation-function measurements, strong heavy-ion resonance behavior has been observed in elastic and inelastic cross sections for the 24Mg - 24Mg system. There has been speculation that peaks observed in the corresponding excitation-energy spectra at more negative Q values may also be a consequence of this resonance phenomenon. The observation of very similar behavior with the asymmetric-mass entrance channels makes it less likely, though, that the peaks arise from any special configuration of the compound system. Instead, an analysis of the γ-ray data and the results of statistical-model calculations support the conclusion that most of the observed high-lying structure can be accounted for in terms of statistical fission from a fully energy- and shape-equilibrated compound nucleus. For the 24Mg + 24Mg entrance channel, however, comparisons with the statistical model indicate a reduction of high-angular-momentum partial cross sections, leading to the 24Mg + 24Mg fission channel. For the first time, we are able to deduce the nature of the competition between the resonance and statistical-fission mechanisms in this mass region.",
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T1 - Fission decay of 48Cr at E*CN≈60 MeV

AU - Farrar, K. A.

AU - Sanders, S. J.

AU - Dummer, A. K.

AU - Hasan, A. T.

AU - Prosser, F. W.

AU - Back, B. B.

AU - Bearden, I. G.

AU - Betts, R. R.

AU - Carpenter, M. P.

AU - Crowell, B.

AU - Freer, M.

AU - Henderson, D. J.

AU - Janssens, R. V F

AU - Khoo, T. L.

AU - Lauritsen, T.

AU - Liang, Yun

AU - Nisius, D.

AU - Wuosmaa, A. H.

AU - Beck, C.

AU - Freeman, R. M.

AU - Cavallaro, Sl

AU - Szanto De Toledo, A.

PY - 1996/9

Y1 - 1996/9

N2 - The fully energy-damped yields for the 36Ar + 12C and 20Ne + 28Si reactions at Ec.m. = 47.0 MeV and 45.5 MeV, respectively, are explored using particle-particle-γ coincidence data. These reactions reach a similar excitation energy of E*CN= 59.5 MeV in the 48Cr compound nucleus as was obtained in an earlier particle-particle coincidence study of the 24Mg + 24Mg reaction. The overall mass and total kinetic energy distributions of the fission fragments are found to be well reproduced by statistical-model calculations. These calculations are also found to reproduce structure seen in the excitation-energy spectra for the 20Ne + 28Si and 24Mg + 24Mg exit channels for all three reactions. In previous excitation-function measurements, strong heavy-ion resonance behavior has been observed in elastic and inelastic cross sections for the 24Mg - 24Mg system. There has been speculation that peaks observed in the corresponding excitation-energy spectra at more negative Q values may also be a consequence of this resonance phenomenon. The observation of very similar behavior with the asymmetric-mass entrance channels makes it less likely, though, that the peaks arise from any special configuration of the compound system. Instead, an analysis of the γ-ray data and the results of statistical-model calculations support the conclusion that most of the observed high-lying structure can be accounted for in terms of statistical fission from a fully energy- and shape-equilibrated compound nucleus. For the 24Mg + 24Mg entrance channel, however, comparisons with the statistical model indicate a reduction of high-angular-momentum partial cross sections, leading to the 24Mg + 24Mg fission channel. For the first time, we are able to deduce the nature of the competition between the resonance and statistical-fission mechanisms in this mass region.

AB - The fully energy-damped yields for the 36Ar + 12C and 20Ne + 28Si reactions at Ec.m. = 47.0 MeV and 45.5 MeV, respectively, are explored using particle-particle-γ coincidence data. These reactions reach a similar excitation energy of E*CN= 59.5 MeV in the 48Cr compound nucleus as was obtained in an earlier particle-particle coincidence study of the 24Mg + 24Mg reaction. The overall mass and total kinetic energy distributions of the fission fragments are found to be well reproduced by statistical-model calculations. These calculations are also found to reproduce structure seen in the excitation-energy spectra for the 20Ne + 28Si and 24Mg + 24Mg exit channels for all three reactions. In previous excitation-function measurements, strong heavy-ion resonance behavior has been observed in elastic and inelastic cross sections for the 24Mg - 24Mg system. There has been speculation that peaks observed in the corresponding excitation-energy spectra at more negative Q values may also be a consequence of this resonance phenomenon. The observation of very similar behavior with the asymmetric-mass entrance channels makes it less likely, though, that the peaks arise from any special configuration of the compound system. Instead, an analysis of the γ-ray data and the results of statistical-model calculations support the conclusion that most of the observed high-lying structure can be accounted for in terms of statistical fission from a fully energy- and shape-equilibrated compound nucleus. For the 24Mg + 24Mg entrance channel, however, comparisons with the statistical model indicate a reduction of high-angular-momentum partial cross sections, leading to the 24Mg + 24Mg fission channel. For the first time, we are able to deduce the nature of the competition between the resonance and statistical-fission mechanisms in this mass region.

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