https://doi.org/10.1140/epja/s10050-024-01368-6
Regular Article - Experimental Physics
Mass distributions in 12C + 232Th fission: role of shell effects and excitation energy
1
Radiochemistry Division, Bhabha Atomic Research Centre, 400085, Mumbai, India
2
Nuclear Physics Division, Bhabha Atomic Research Centre, 400085, Mumbai, India
3
Homi Bhabha National Institute, 400094, Mumbai, India
Received:
31
January
2024
Accepted:
23
June
2024
Published online:
15
July
2024
This article reports the measurement of cross sections of charge and mass identified fission products and the mass distributions in 232Th(12C,f) reaction at 62.5, 70.7 and 102.9 MeV beam energies to investigate the role of single particle effects. The study was carried out using the recoil catcher technique followed by off-line γ-ray spectrometry. Cross sections of 32, 54 and 64 fission products were measured for 62.5, 70.7 and 102.9 MeV beam energies, respectively. The mass distributions obtained at 62.5 and 70.7 MeV show a flat-top nature indicating significant asymmetric fission contribution (heavy mass peak corresponding to Z range of 54–56), whereas, a nearly Gaussian behaviour was observed at 102.9 MeV indicating dominant contribution from symmetric fission. The experimental mass distributions were in gross agreement with the “GEF, 2021/1.1” calculations which predicted significant asymmetric fission contribution dominated by Z ≈ 55 (‘Standard 2’ mode) at 62.5 and 70.7 MeV. The present study shows the significant role of charge polarization resulting in the deviation of the most probable charge (ZP) values from those obtained using UCD hypothesis. “GEF, 2023/2.1” calculations were unable to explain the observed mass distributions with significant asymmetric fission contribution due to comparatively lower contribution from higher chance fission resulting from the lower saddle point energies. An attempt has been made to estimate the mass distributions arising from the complete fusion fission and α-transfer induced fission. The trend shows an increase in the α-transfer induced fission contribution with increasing beam energy which is in qualitative agreement with the sum-rule model calculations.
© The Author(s) 2024
Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
