Fragment dependence of high energy
-ray emission in the spontaneous
fission of 252Cf
D.C. Biswas1 - B.K. Nayak1 - M. Cinausero2 - B. Fornal3 - G. Viesti4 - D. Bazzacco4 - M. DePoli2 - D. Fabris4 - E. Fioretto2 - M. Lunardon4 - D.R. Napoli2 - G. Nebbia4 - G. Prete2 - C.A. Ur4 - G. Vedovato2
1 Bhabha Atomic Research Centre, Mumbai, India
2 I.N.F.N., Laboratori Nazionali di Legnaro, Via Romea, 4, I-35020 Legnaro, Italy
3 Institute of Nuclear Physics, Krakow, Poland
4 Dipartimento di Fisica and INFN, Sezione di Padova, Padova, Italy
Received: 22 December 1998 Communicated by D. Schwalm
Abstract
The high energy -ray emission accompanying the spontaneous
fission of 252Cf has been measured in coincidence with individual
fission fragments selected by discrete
-ray transitions.
The enhancement of the
-ray emission probability in the energy range
E
=3-8 MeV has been observed for the fission fragments
in the region of nearly symmetric mass splitting, confirming results reported
in previous investigations.
The
-
coincidence technique employed in the present work
clearly demonstrate that the major
contribution to this enhancement is caused by the fission channels
where one fragment is near to the N=82 or Z=50 shell closures. The
high energy
-ray emission probability does not show any significant
dependence on the number of neutrons emitted in the fission process,
supporting the hypothesis that high energy
-rays are mainly
emitted from the fragments after the neutron evaporation.
PACS
25.85.Ca Spontaneous fission -
23.20.Lv Gamma transitions and level energies -
27.60.+j
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