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Project List » Giant Quadrupole Resonance (GQR) possible alpha decay in neutron-induced reactions

Giant Quadrupole Resonance (GQR) possible alpha decay in neutron-induced reactions

Acronym: GQRpad
Contracting Authority: UEFISCDI
Number / Date of the contract: PN-III-ID-PCE-2021-1260 /
PN-III-P4 Cercetare fundamentala si de frontiera
Project Manager: Vlad Avrigeanu
Starting date / finishing date: 2022-06-01 / 2025-02-28
Project value: 1200000 RON
Abstract: Description of a-particle emission from nuclei excited in fast-neutron induced reactions, of equal large interest for nuclear astrophysics and fusion technology, is severely constrained by the a-particle optical model potential (OMP) at energies around the Coulomb barrier B. However, an open question has just been shown to remain on a significant contribution at energies of Giant Quadrupole Resonances (GQR), to (n, a) reaction excitation functions. On the other hand, widely-used OMP phenomenological parameters were formerly obtained by analysis of a-particle elastic-scattering, which is ruled out below B, and a-induced reaction data at the energies E
Objectives: The overall objective of this project proposal is a suitable assessment of the a-particle emission and OMP at low energies (E<50 MeV), for the incident and the outgoing reaction channel as well, with the largest attention paid to energies around and below B which are of first interest for both nuclear technology and nuclear astrophysics. It should be underlined the yet open discussion on this subject in spite of its long-standing demand and actual needs of definite conclusions. The achievement of this objective is related, on the other hand, to several specific objectives. (i) Beyond the involvement of the rather long-standing statistical model (SM) framework, there are quite accurate recent data indicating that additional mechanisms should be taken into account and could be validated on their basis, i.e. the pick-up DR contribution, to be considered in addition to PE+SM even below a neutron-incident energy of 10 MeV, and a GQR component to account for a particular shoulder around the incident energy of ~12 MeV. However, additional accurate distorted-wave Born approximation (DWBA) analysis is aimed in this project for the former case, with no further empirical normalization in order to describe the a-emission experimental data and support the GQR hypothesis. (ii) Because it is still considered that there is no global OMP even for the incident a-particles, an objective of this project should also concern the accuracy of the (α,x) reaction cross sections calculated by using our alpha-particle global OMP established within the mass range 45<=A<=209. Thus, it is mandatory to check this OMP within SM calculations for any forthcoming (α,x) reaction data. (iii) The suitable description of the particular (a,g) reaction cross sections depends a lot also on the adoption of a correct radiative strength function (RSF) model. This has been the case of many recent (α,γ) reaction data, including the analysis of the calculated cross-section sensitivity to various RSF forms. Similar discussion of any forthcoming RSF and (α,γ) reaction data is also mandatory. (iv) The (x,α) reaction cross-section discussion is mainly related to the possible OMP for a-particle emitted from hot excited nuclei, at variance or not to the OMP proved suitable for a-particle incident on cold target nuclei. Therefore, it could be most useful to look for extension of our analysis of new (p,α) reaction data proved to be well described by the same OMP as for the incident channel. This conclusion should be validated for more cases.

1. PCE-2021 Project Proposal as generated by UDIManager; , Project No. 164 (2021-07-07) Results
2. OpenPosition_MsC-PhD_ASC_PCE-2021-1260 (2022-05-27) Results
3. Consistent analysis of nucleon-induced reactions on 93Nb nucleus, including particularly a-emission, at energies below and around the Coulomb barrier  (2022-12-31) Results
4. Consistent analysis of nucleon-induced reactions on Mo isotopes, including particularly α-emission, at energies below and around the Coulomb barrier (2023-12-31) Results
5. Consistent analysis of nucleon-induced reactions on heavy target nuclei, including particularly α-emission, at energies below and around the Coulomb barrier  (2025-02-28)
RESULTS [Project Activity Report]

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