Study of preequilibrium decay in (α,xn) reactions in holmium up to 70 MeV

Abstract

Alpha particle induced reactions on the target element holmium were investigated upto 70 MeV using stacked foil activation technique and Ge(Li) gamma ray spectroscopy methods. Excitation functions for the formation of reaction residues 168Tm, 167Tm, 166Tm and 165Tm from α-induced reactions on 165Ho were investigated for the first time in the energy range from 50-70 MeV. The measured cross sections were compared with theoretical calculations considering equilibrium as well as preequilibrium hybrid models of Blann. The high energy tails of the excitation functions show a substantial contribution from preequilibrium emission. A general agreement is observed between the experimental results and theoretical predictions with an initial excition configuration of n0 = 4(4p 0h).

Non-equilibrium emission of neutrons in α-particle induced reactions with holmium

“…In Fig. 5, the results of Singh et al [14] show considerable deviation in the energy range 34-40 MeV, while the results of Gadkari et al [13] are lower than our results and the theoretically calculated values in the energy region 45-50 MeV. Our results are in better agreement with theoretical predictions for PE with equilibrium calculations in the high-energy tail of the excitation functions.…”

“…As shown in Fig. 4, the results of Singh et al [14] are much lower than our results and the results of Gadkari et al [13] in the energy region (31-38 MeV). However, our results are in better agreement with the results of Gadkari et al [13] in the energy region 30-46 MeV, while at 50.2 MeV the result of Gadkari et al [13] is much lower than ours and the theoretically calculated value.…”

“…It can be seen from Fig. 3 that the results of Gadkari et al [13] are much lower than our results in the high-energy region (32)(33)(34)(35)(36)(37)(38)(39)(40)(41)(42)(43)(44)(45)(46)(47)(48)(49)(50); however at 32 MeV the result of Singh et al [14] is much lower than ours. As shown in Fig.…”

“…The measured excitation functions for the reactions 165 Ho(α, 2n) 167 [13,14]. The theoretical excitation functions calculated with and without inclusion of PE emission via ALICE-91 code are represented by continuous and dotted lines, respectively.…”

“…Moreover, the data are incomplete and contain considerable errors. Although the excitation functions for holmium were measured by other groups [13,14], their results differ to a large extent, hence precise and accurate measurements are still needed. With this motivation, the present work was undertaken to measure the excitation functions for 165 Ho with up to 50 MeV α-particle energy.…”