Intriguing features of the prompt fission $$\gamma $$-ray spectra in the fast neutron induced fission of $$^{232}$$Th
Year: 2025
Type: article
Abstract: Prompt fission $$\gamma $$ γ -ray spectra (PFGS) extending to very low photon energies have been measured in the $$^{232}$$ 232 Th(n,f) reaction over a range of incident neutron energies below the second chance fission threshold, for which no data are available. Fission events were detected with an ionization chamber containing $$^{232}$$ 232 Th foils, and the coincident prompt fission $$\gamma $$ γ -rays were detected using two CeBr $$_{3}$$ 3 scintillation detectors. The measured spectra were unfolded using the corresponding response matrices of the detectors, simulated using Geant4, to obtain the PFGS in the $$\gamma $$ γ -ray energy region of 0.1–1.2 MeV. Surprisingly, significant reduction in photon intensity is observed for the $$^{232}$$ 232 Th(n,f) reaction below the photon energy of 0.4 MeV when compared with the available data of $$^{238}$$ 238 U(n,f) and $$^{239}$$ 239 Pu(n,f) reactions at similar excitation energies. Moreover, the average $$\gamma $$ γ -ray multiplicity, $$\bar{M_\gamma }$$ M γ ¯ , is found to be $$\sim 40\%$$ ∼ 40 % lower and the average photon energy, $$\epsilon _{\gamma }$$ ϵ γ , is found to be $$\sim 50\%$$ ∼ 50 % higher for $$^{232}$$ 232 Th(n,f) reaction as compared to $$^{238}$$ 238 U(n,f) and $$^{239}$$ 239 Pu(n,f) reactions in the $$\gamma $$ γ -ray energy region of $$0.1-1.2$$ 0.1 - 1.2 MeV. It is found that the GEF model fails to predict the observed features of the PFGS in the $$^{232}$$ 232 Th(n,f) reaction. The present experi
Source: The European Physical Journal A
Institutions: Bhabha Atomic Research Centre, Homi Bhabha National Institute
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,990
Funder: Bhabha Atomic Research Centre
OpenAlex ID: W4408055835