Abstract
Full text: In heavy-ion induced fusion-fission reactions, the angular distribution of fission fragments is sensitive to the mean square angular momentum brought in by the fusion process, and the nuclear shape and temperature at the fission saddle point. Experimental fission fragment angular distributions are often used to infer one or more of these properties. A new theoretical approach, incorporated into a computer code, allows the effect of ground-state spin of the projectile and target nuclei to be incorporated. Measurements recently completed agree with these predictions. We have made further predictions, appropriate to reactions on the strongly deformed isomeric state in {sup 178}Hf, which has a half-life of 31 years and a spin of 16. These reactions would result in fission fragment angular distributions with characteristics unlike any others. In particular, the anisotropy (defined as the ratio of the yield at 0 deg or 180 deg to the yield at 90 deg) may be less than unity, in stark contrast with anisotropies for almost any other heavy ion reaction. Other unique characteristics of the distributions will be discussed, together with the reasons for the unique behaviour, and we will assess the prospects of measurements being carried out on this target.
Butt, R
[1]
- Australian National University, Canberra, ACT (Australia). Nuclear Physics Department
Citation Formats
Butt, R.
Exotic fission fragment angular distributions.
Australia: N. p.,
2002.
Web.
Butt, R.
Exotic fission fragment angular distributions.
Australia.
Butt, R.
2002.
"Exotic fission fragment angular distributions."
Australia.
@misc{etde_20619755,
title = {Exotic fission fragment angular distributions}
author = {Butt, R}
abstractNote = {Full text: In heavy-ion induced fusion-fission reactions, the angular distribution of fission fragments is sensitive to the mean square angular momentum brought in by the fusion process, and the nuclear shape and temperature at the fission saddle point. Experimental fission fragment angular distributions are often used to infer one or more of these properties. A new theoretical approach, incorporated into a computer code, allows the effect of ground-state spin of the projectile and target nuclei to be incorporated. Measurements recently completed agree with these predictions. We have made further predictions, appropriate to reactions on the strongly deformed isomeric state in {sup 178}Hf, which has a half-life of 31 years and a spin of 16. These reactions would result in fission fragment angular distributions with characteristics unlike any others. In particular, the anisotropy (defined as the ratio of the yield at 0 deg or 180 deg to the yield at 90 deg) may be less than unity, in stark contrast with anisotropies for almost any other heavy ion reaction. Other unique characteristics of the distributions will be discussed, together with the reasons for the unique behaviour, and we will assess the prospects of measurements being carried out on this target.}
place = {Australia}
year = {2002}
month = {Jul}
}
title = {Exotic fission fragment angular distributions}
author = {Butt, R}
abstractNote = {Full text: In heavy-ion induced fusion-fission reactions, the angular distribution of fission fragments is sensitive to the mean square angular momentum brought in by the fusion process, and the nuclear shape and temperature at the fission saddle point. Experimental fission fragment angular distributions are often used to infer one or more of these properties. A new theoretical approach, incorporated into a computer code, allows the effect of ground-state spin of the projectile and target nuclei to be incorporated. Measurements recently completed agree with these predictions. We have made further predictions, appropriate to reactions on the strongly deformed isomeric state in {sup 178}Hf, which has a half-life of 31 years and a spin of 16. These reactions would result in fission fragment angular distributions with characteristics unlike any others. In particular, the anisotropy (defined as the ratio of the yield at 0 deg or 180 deg to the yield at 90 deg) may be less than unity, in stark contrast with anisotropies for almost any other heavy ion reaction. Other unique characteristics of the distributions will be discussed, together with the reasons for the unique behaviour, and we will assess the prospects of measurements being carried out on this target.}
place = {Australia}
year = {2002}
month = {Jul}
}