Pion-Induced Fission of 209Bi and 119Sn:. Measurements, Calculations, Analyses and Comparison
Abstract
Cross-sections for the π--induced fission of 209Bi and 119Sn have been measured using the most sensitive CR-39 solid-state nuclear track detector. In experiments, target-detector stacks were exposed to negative pions of energy 500, 672, 1068, and 1665 MeV at the Brookhaven National Laboratory, USA. An important aspect of the present paper is the comparison of pion-induced fission fragment spectra of above mentioned nuclei with the spontaneous fission fragment spectra of 252Cf. This comparison is made in terms of fission fragment track lengths in the CR-39 detectors. Measurement results are compared with calculations of Monte Carlo and statistical weight functions methods using the computer code CEM95. Agreement between measurements and calculations is fairly good for 209Bi target nuclei whereas it is indigent for the case of 119Sn. The possibilities of the trustworthy calculations, using the computer code CEM95, comparable with measurements of pion-induced fission in intermediate and heavy nuclei are explored by employing various systematics available in the code. Energy dependence of pion-induced fission in 119Sn and 209Bi is analyzed employing a newly defined parameter geometric-size-normalized fission cross-section (χfg). It is found that the collective nuclear excitations, which may lead to fission, become more probable for both 209Bi and 119Sn nuclei with increasing energy of negative pions from 500 to 1665 MeV.
- Publication:
-
International Journal of Modern Physics E
- Pub Date:
- 2011
- DOI:
- 10.1142/S0218301311019593
- Bibcode:
- 2011IJMPE..20.1709R
- Keywords:
-
- Pion-induced fission cross-sections;
- spontaneous fission;
- nuclear track detector CR-39;
- cascade exciton model;
- fission barrier;
- survival probability;
- 25.80.Hp;
- 24.60.Dr;
- Pion-induced reactions;
- Statistical compound-nucleus reactions