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Astrophysical reactions involving radioactive isotopes (RI) often play an important role in high-temperature stellar environments. The experimental studies on the reaction rates for those are still limited mainly due to the technical difficulties in producing high-quality RI beams. A direct measurement of those reactions would be still challenging in many cases, however, we can make a reliable evaluation of the reaction rates by an indirect method or by studying the resonance prorerties. Here we ntroduce recent examples of experimental studies on such RI-involving astrophysical reactions, performed at Center for Nuclear Study, the University of Tokyo, using the low-energy RI beam separator CRIB. One is for the neutron-induced destruction reactions of 7Be in the Big-Bang nucleosynthesis, and the other is the study on the 22Mg(α, p) reaction relevant in X-ray bursts, which was performed with the resonant scattering method from the inverse reaction channel.

Experimental studies on astrophysical reactions involving radioactive isotopes (RI) often accompany technical challenges. Studies on such nuclear reactions have been conducted at the low-energy RI beam separator CRIB, operated by Center for Nuclear Study, the University of Tokyo. We discuss two cases of astrophysical reaction studies at CRIB; one is for the 7Be+n reactions which may affect the primordial 7Li abundance in the Big-Bang nucleosynthesis, and the other is for the 22Mg(α, p) reaction relevantin X-raybursts.

Background: The Li 6 ( p , γ ) Be 7 cross section influences a variety of astrophysical scenarios, including big-bang and stellar nucleosynthesis. In recent years, conflicting results of direct measurements have been published, reporting contradictory low-energy trends. Purpose: To shed light on the contradiction between the existing data sets, the reaction was studied using the asymptotic normalization coefficient (ANC) technique which was up-to-now never used for this reaction. Methods: To derive the ANC, the Li 6 ( He 3 , d ) Be 7 transfer reaction, studied at the Department of Physics and Astronomy of the University of Catania and at the John. D. Fox Superconducting Accelerator Laboratory at Florida State University, was re-analyzed, focusing on the proton transfer mechanism [the α transfer process is discussed by Kiss et al. [Phys. Lett. B 807, 135606 (2020)]. The energy of the He 3 beam impinging on a Li 6 target was E lab = 3 MeV and E lab = 5 MeV. The yield of the emitted deuterons was measured with high precision by using silicon Δ E - E telescopes. Results: From the DWBA analysis of the angular distributions of the emitted deuterons populating the ground ( E * = 0.0 MeV; 3 2 − ) and the first excited ( E * = 0.429 MeV ; 1 2 − ) states of Be 7 , the ANCs for the Li 6 + p → Be 7 system were deduced. Furthermore, the recently measured Li 6 ( p , γ ) Be 7 reaction cross sections [Piatti , Phys. Rev. C 102, 052802 (2020)] were also analyzed within this theoretical framework. Excellent agreement was found between ANC values derived indirectly and those determined from the direct data, which strengthens the conclusion of the present work. The astrophysical S factor—at energies characterizing the Sun—for the Li 6 ( p , γ ) Be 7 reaction was calculated using the weighted mean of the experimentally derived ANC values. Conclusions: The result of the present comprehensive study supports the extrapolation of Piatti [Phys. Rev. C 102, 052802 (2020)], Dong [J. Phys. G Nucl. Partic. 44, 045201 (2017)], and Gnech and Marcucci [Nucl. Phys. A 987, 1 (2019)], and thus disfavors the conclusions drawn by He [Phys. Lett. B 725, 287 (2013)] and Xu [Nucl. Phys. A 918, 61 (2013)].

The neutron capture reaction $$^{10}$$ B(n, $$\alpha $$ ) $$^{7}$$ Li has been investigated via the Trojan Horse Method from 0 to 1 MeV. The $$\alpha _{0}$$ and $$\alpha _{1}$$ channels, corresponding to $$^{7}$$ Li in its g.s. and 1st excited level respectively, have been analyzed and cross sections have been measured for the two reaction channels. Angular distributions for the $$^{11}$$ B energy levels in the explored range have been extracted and compared with literature, while the J $$^{\pi }$$ of the level at $$E_{11B}=11.450$$ MeV (4 keV before the $$\alpha $$ emission threshold) has been clearly determined for the first time.

The $^{26}\mathrm{Si}(p,\ensuremath{\gamma})^{27}\mathrm{P}$ reaction might be relevant in understanding the $^{26}\mathrm{Si}$ depletion and $^{26}\mathrm{Al}$ production in stars. The asymptotic normalization coefficients (ANC) for the $^{26}\mathrm{Si}(p,\ensuremath{\gamma})^{27}\mathrm{P}$ reaction were extracted earlier from the reanalysis of $^{26}\mathrm{Mg}(d,p)^{27}\mathrm{Mg}$ and $^{26}\mathrm{Mg}(t,d)^{27}\mathrm{Mg}$ reactions, in which the deduced ANC's show significant discrepancies. In this work, a dedicated ($d,p$) measurement is presented: the ANC for the $^{27}\mathrm{Mg}\ensuremath{\rightarrow}\phantom{\rule{0.16em}{0ex}}^{26}\mathrm{Mg}+n$ virtual decay is deduced from the $^{26}\mathrm{Mg}(d,p)^{27}\mathrm{Mg}$ reaction populating the ground and the first excited state of $^{27}\mathrm{Mg}$ using the distorted wave Born approximation (DWBA). The charge symmetry properties for mirror nuclei have been used to calculate the ANC for the direct capture $^{26}\mathrm{Si}+p\ensuremath{\rightarrow}\phantom{\rule{0.16em}{0ex}}^{27}\mathrm{P}$ populating the ground state of $^{27}\mathrm{P}$. By means of the same formalism, the ${\mathrm{\ensuremath{\Gamma}}}_{p}$ width for the first excited state has also been deduced. The reaction rate is also updated using recent values for the ${\mathrm{\ensuremath{\Gamma}}}_{\ensuremath{\gamma}}/{\mathrm{\ensuremath{\Gamma}}}_{p}$ ratio measured by [Sun et al., Phys. Rev. C 99, 064312 (2019); Sun et al., Phys. Lett. B 802, 135213 (2020)].

For the first time in an application to nuclear astrophysics, a process induced by the unstable $$^5$$ He = ( $$^4$$ He-n) nucleus, the $$^3$$ He+ $$^5$$ He $$\rightarrow $$ 2 $$\alpha $$ reaction, has been studied through the Trojan Horse Method (THM). For that purpose, the quasi-free (QF) contribution of the $$^9$$ Be( $$^3$$ He, $$\alpha \alpha $$ ) $$^4$$ He reaction was selected at $$E_{^{3}\text{ He }}=4$$ MeV incident energy. The reaction was studied in a kinematically complete experiment following a recent publication (Spitaleri et al. in Eur Phys J A 56:18, 2020), where for the quasi free contribution the momentum distribution between $$\alpha $$ and $$^5$$ He particle cluster in the $$^9$$ Be nucleus in the ground state have been extracted. The angular distribution of the QF $$^3$$ He+ $$^5$$ He $$\rightarrow $$ 2 $$\alpha $$ reaction was measured at $$\theta _{cm}$$ = 78 $$^{\circ }$$ –115 $$^{\circ }$$ . The energy dependence of the differential cross section of the $$^3$$ He+ $$^5$$ He $$ \rightarrow $$ 2 $$\alpha $$ virtual reaction was extracted in the energy range $$E_{cm}$$ = 0–650 keV. The total cross section obtained from the Trojan-horse method was normalized to absolute cross sections from a theoretical calculation in the energy range $$E_{cm}$$ =300–620 keV.

Nuclear reactions play a key role in the framework of the Big Bang Nucleosynthesis. A network of 12 principal reactions has been identified as the main path that drove the elemental nucleosynthesis in the first 20 min of the history of the Universe. Among them an important role is played by neutron-induced reactions, which, from an experimental point of view, are usually a difficult task to be measured directly. Nevertheless big efforts in the last decades have led to a better understanding of their role in the primordial nucleosynthesis network. In this work we apply the Trojan Horse Method to extract the cross section at astrophysical energies for the $$^3\text {He}$$ (n,p) $$^3\text {H}$$ reaction after a detailed study of the $$^2\hbox {H}$$ ( $$^3\text {He}$$ ,pt)H three-body process. Data extracted from the present measurement are compared with other published sets.

Among the indirect methods to determine nuclear cross-section present in literature, the so-called Asymptotic Normalization Coefficient (ANC) has proven to be useful in retrieving the direct part of a radiative capture cross-section in reactions of interest for astrophysics. In this work, the method will be presented, and some results obtained in collaboration between NPI CAS and INFN-LNS will be presented.

A new study of the quasi-free contribution to the $$^3\hbox {He}+\,^9\hbox {Be}\rightarrow 3\alpha $$ reaction (Q value = 19.004 MeV) at low $${E}_{^3{{\mathrm{He}}}}$$ energy is presented. The reaction was studied in a kinematically complete experiment at beam energy of 4 MeV. To clarify the presence of the quasi-free mechanism, the $$^4{\hbox {He}}$$–$$^5\hbox {He}$$ momentum distribution of the $$^9\hbox {Be}$$ ground state was extracted. Standard tests were also carried out to confirm the presence of the quasi-free contribution and are reported in this work. The full width at half maximum of the $$^4\hbox {He}$$–$$^5\hbox {He}$$ inter-cluster momentum distribution inside $$^9\hbox {Be}$$ was measured with improved accuracy, by adopting several different approaches that all led to consistent results. These preliminary investigations on the reaction mechanism are fundamental for future studies employing the Trojan Horse Method, with the $$^5\hbox {He}$$ unbound nucleus as a virtual projectile.

Neutron induced reactions are fundamental for the nucleosynthesis of elements in the universe. Indeed, to correctly study the reactions involved in the well-known s-process in stars, which produce about half of the elements beyond the iron peak, it is mandatory to know the neutron abundance available in those stars. The 17O(n, a)14C reaction is one of the so-called “neutron poisons” for the pro- cess and it could play an important role in the balance of the neutron abundance. The reaction is therefore investigated in the energy range of astrophysical inter- est between 0 and 350 keV in the center of mass by applying the Trojan Horse Method to the three body reaction 2H(17O, a14C)H.

In the network of reactions present in the Big Bang nucleosynthesis, the 3He(n, p)3H has an important role which impacts the final 7Li abundance. The Trojan Horse Method (THM) has been applied to the 3He(d, pt)H reaction in order to extract the astrophysical S(E)-factor of the 3He(n, p)3H in the Gamow energy range. The experiment will be described in the present work together with the first preliminary results.

Abundance of 19F exceeds by far the predicted one. This problem represents one of the unanswered questions of stellar modelling. A source of large uncertainties at relevant energies are the 19F(p, α)16O and 19F(α, p)22Ne reactions. Although the lowest energy point from direct experiments are at about ∼660 keV, the astrophysical relevant energy region is only known by R-Matrix calculations. In this work we apply the Trojan Horse Method (THM) to the appropriate quasi-free three-body reactions. The THM application allowed us to study the sub-Coulomb energy region and to get the corresponding S(E)-factor values, thus allowing for a detailed evaluation of its astrophysical impact.

We discuss experimentally and theoretically neutron production from the laser driven explosion of gas clusters prepared near the liquid-gas critical point. We let deuterated methane that was prepared very close to its critical temperature and pressure expand through a conical nozzle to create clusters, and then irradiated those clusters with a high intensity pulse from the Texas Petawatt Laser. After ionization, the clusters explode producing energetic ions, some of which fuse with resultant neutron emission. We show that the critical fluctuations present in the nozzle before the expansion influence the dynamics of neutron production. Neutron production near the critical point follows a power law, which is a signature of a second order phase transition and it is consistent with the Fisher model. This result might be relevant for energy production from fusion reactions.

The Trojan Horse Method represents an indirect approach to investigate reactions of astrophysical relevance at the energies of interest, free of Coulomb suppression and electron screening effects. In this review, we will examine how the Trojan Horse Method has evolved from the study of the quasi-free reaction mechanism. We will first present the basic features of the quasi-free reaction mechanism in the framework of the theory of direct reactions, from quasi-free scattering to quasi-free reactions processes, and its evolution towards the Trojan Horse Method with its modern theory. We will review the validity tests to assess the technique, the procedure to analyze the data and to extract the astrophysical factor. Finally, we will discuss some of the most important experimental results recently published related to nuclear astrophysics and applications.

In AGB environment, Fluorine and Sodium production and destruction pathways are still not completely understood: their abundances are therefore still matter of debate. \(^{19}\mathrm {F}\) (only stable isotope of fluorine) abundance is strongly related to standard and extra-mixing processestype typical of the interior AGB-stars. Furthermore, the destruction channels for this element are far from being well understood. About \(^{23}\)Na, its presence in Globular Clusters along with the well-known anticorrelation with oxygen, underline that this element has been produced in previous generations of stars: in particular, intermediate-mass AGB stars are one of the possible candidates for its production. For this reason we studied the \(^{19}\mathrm {F}\)(\(\alpha \),p)\(^{22}\mathrm {Ne}\) and \(^{23}\mathrm{Na}(\mathrm{p},\alpha )^{20}\)Ne reactions in the energy range of relevance for astrophysics via the Trojan Horse Method (THM), using the three-body reactions \(^{6}\mathrm {Li}\)(\(^{19}\mathrm {F}\), p\(^{22}\mathrm {Ne}\))d and \(^{23}\mathrm {Na}\) (d, pn)\(^{20}\mathrm {Ne}\).

Owing the presence of the Coulomb barrier at astrophysically relevant kinetic energies, it is very difficult, or sometimes impossible to measure astrophysical reaction rates in laboratory. To overcome the problems related to the use of extrapolation procedure, the Trojan Horse Method (THM) has been applied extensively for the last 25 years to measure nuclear reaction cross sections of astrophysical interest. Although it has been mainly applied for charged particle-induced reactions, recently the THM has been found to have also a relevant role for neutron-induced ones. Here, the basic principle and a review of the main application of the Trojan Horse Method are presented, following a step-by-step description of the results concerning the study of the 17O(n,α)14C reaction.

The \(^{19}\)F(p,\(\alpha \))\(^{16}\)O reaction is an important channel of fluorine destruction in H-rich environments as the outer layers of Asymptotic Giant Branch (AGB) stars. Measurements of the \(^{19}\)F(p,\(\alpha _0\))\(^{16}\)O reaction via the Trojan Horse Method (THM) have shown the presence of resonant structures not observed before. As a consequence, the reaction rate at astrophysical temperatures (about \(10^{7}\)–\(10^{8}\) K) exceeds up to a factor 1.7 the one previously adopted. Here we present the result of an experiment in which THM was used to extract the Quasi-Free (QF) contribution of the \(^{2}\)H(\(^{19}\)F,\(\alpha \) \(^{16}\)O)n reaction to the \(^{19}\)F(p,\(\alpha _1\))\(^{16}\)O channel, corresponding to the population of the first excited state of the \(^{16}\)O. Three resonances in the E\(_{cm}\) energy region below about 500 keV have been observed. This result hints to an enhancement of the \(^{19}\)F(p,\(\alpha \))\(^{16}\)O destruction rate, with respect to what presently predicted.

In the framework of the experimental campaign of the ($ p,\alpha$) and ($ n,\alpha$) reactions cross sections measurement involving the 10, 11B isotopes, different ($ n,\alpha$) cross section measurements have been performed at ultra-low energy. In this work, the 10B(n,$ \alpha$)7Li reaction was investigated through the Trojan Horse Method, by means of the Quasi-Free (QF) 2H(10B,$ \alpha^{7}$Li)1H reaction at 30 MeV of beam energy. As in the standard THM approach, the measurement has been performed in inverse kinematics using a 10B beam. The excitation function of the 10B(n,$ \alpha$)7Li reaction has been measured at a center-of-mass energy between 0 and 700 keV. The data were compared with the existing experimental ones. Even if the energy resolution of the present experiment did not allow a separation between the channels ($ n,\alpha_0$) and ($ n,\alpha_1$) the low energy cross section and the angular distribution are presented, pointing out once more the ability of the method in studying neutron induced reactions using deuteron as source of virtual neutrons.

We present the progress in the measurements of the nuclear reaction rates for \(^{6,7}\)Li, \(^9\)Be and \(^{10}\)B (p,\(\alpha \)) burning channels derived using the Trojan Horse Method (THM). The effects on the predicted stellar surface abundances of such elements in pre-main sequence stars are evaluated using the Pisa up-to-date stellar evolutionary code. The present analysis is restricted to the pre-MS evolution of low-mass stars.

We performed indirect measurements of the neutron-induced reactions \(^{7}\)Be(n,p)\(^{7}\)Li and \(^{7}\)Be(n,\(\mathsf \alpha \))\(^{4}\)He simultaneously by the Trojan Horse method relevant to the cosmological \(^7\)Li problem. Preliminary excitation functions for \((n,p_0)\) and \((n,\alpha )\) are basically consistent with the previous studies, and new information about the \((n,p_1)\) contribution suggests possible enhancement of the total reaction rate.

The cosmologically relevant \(^7\)Be(n,\(\alpha \))\(^4\)He has been matter of recent studies aimed at contributing to the long-standing Li-problem. Here a brief description of the twin THM investigations will be shown and the main results discussed.

The Trojan Horse Method has been applied to many neutron-induced reactions using the deuteron as a virtual source of neutrons, to explore wide energy regions of interest for astrophysics and applied physics and to investigate the suppression of the centrifugal barrier, that is one of the key advantages of this Method. The neutron-induced experimental campaign has already concerned 17O(n, α)14C, 6Li(n,α)3H, 7Be(n,p)7Li, 7Be(n,α)4He, 18F(n,α)15O and 14N(n,p)14C, and very recently 25Mg(n,α)22Ne and 27Al(n,p)27Mg, while others are planned to be measured soon, thus influencing different astrophysical scenarios. Particular attention is dedicated to a new measurement regarding the 10B(n,α)7Li reaction, aimed to disentangle the 7Li ground state contribution from its first excited state to the cross section.

An experiment was performed by means of Trojan Horse Method (THM) at the LNS Tandem in Catania. The investigation of the relevant 19F(p,α)16O two-body reaction was performed by selecting the quasi free (QF) contribution of the 19F(2H,α16O)n three-body reaction, using the deuteron target as TH nucleus. The aim of this measurement is to obtain the 19F(p,α)16O cross section. The experimental set-up and the calibration of the detectors will be presented.

The depletion of 18O via the $(\mathrm{p},\gamma)$ capture competes with the $(\mathrm{p}, \alpha)$ capture during the CNO cycles in AGB stars. Despite the fact that the $(\mathrm{p}, \alpha)$ capture is dominant, the $ (\mathrm{p}, \gamma)$ can play an important role in mixing stages of the AGB star evolution. Here, we attempt to determine the astrophysical S-factor of the direct part of the 18O(p,$\gamma$)19F capture by the indirect method of asymptotic normalization coefficients (ANC). We measure the differential cross section of the transfer reaction 18O(3He, d)19F at a 3He energy of 24.6 MeV. The measurement was performed on the cyclotron of the CANAM infrastructure of NPI in Řež, Czech Republic, with the gas target consisting of the high-purity 18O (99.9%). The reaction products were measured by eight $ \Delta E$-E telescopes composed of thin and thick silicon surface-barrier detectors. The parameters of the optical model for the input channel were deduced by means of the code ECIS and the analysis of transfer reactions to 12 levels of the 19F nucleus up to 8.014 MeV was made by the code FRESCO. The deduced ANCs were then used to specify the direct contribution to the 18O(p,$\gamma$)19F capture process and were compared with the mutually different results of two works.

The \(^{12}\)C(\(^{12}\)C,\(\alpha _{0,1}\))\(^{20}\)Ne and \(^{12}\)C(\(^{12}\)C,\(p_{0,1}\))\(^{23}\)Na reactions, which determine carbon burning in stars, have been measured from E\(_{c.m.}\) = 2.7 MeV down to 0.8 MeV via the Trojan Horse Method off the deuteron in \(^{14}\)N. This range of energies is relevant for several astrophysical scenarios, from superburst ignition to hydrostatic burning. The measured astrophysical S(E) factors reveal several resonances, which are responsible for a very large increase of the reaction rate at the relevant temperatures.

The 10B(p,$\alpha_{1}$)7Be reaction has been studied for the first time via the Trojan Horse Method (THM) applied to the 2H(10B,$\alpha$7Be)n quasi-free three-body process. The present experiment allowed for a clear separation between $ \alpha_{0}$ and $\alpha_{1}$ channels thanks to the improved energy resolution with respect to previous THM studies of the 2H(10B,$\alpha$7Be)n reaction. The extracted half-off-energy-shell cross section was found to be characterized by several structures attributable to the population of 11C. In particular, six resonances have been observed at 10.086, 10.352, 10.525, 10.686, 10.841 and 10.976 MeV 11C excitation energy.

In equation (1) of this Letter, the closing bracket was missing; in Extended Data Fig. 1 and the accompanying legend, 'Φ(p

The basic condition for Efimov states is the existence of resonant two-body forces. A system of three particles with resonant two-body interactions may form bound states, the so called Efimov trimers, even when any two of the particles are unable to bind. Inspired by this idea we have analysed a set of data from the $$^6\hbox {Li}+^6\hbox {Li}\rightarrow 3 \alpha $$ reaction measured in a kinematically complete experiment at 3.1 MeV of beam energy, corresponding to 29.6 MeV of excitation energy in $$^{12}\hbox {C}$$ , with the characteristic that the 3 $$\alpha $$ channel is fed by three $$^8\hbox {Be}$$ states in the same event. A strong enhancement in the $$\alpha $$ – $$\alpha $$ coincidence yield is experienced for these events. Evidence of three $$^8\hbox {Be}$$ levels within the same 3 $$\alpha $$ event suggests that one particle is exchanged between the other two. According to quantum mechanics, this is a condition for Efimov states to occur and for which no observation exists yet in nuclei. The hyperspherical formalism for the low-energy three-body problem has been applied to point out the 3 $$\alpha $$ particle correlation.

Present and future gamma-beam facilities represent a great opportunity to validate and evaluate the cross-sections of many photonuclear reactions at near-threshold energies, whose data mostly come from theoretical calculations. We developed a Monte Carlo (MC) software that makes use of the validatedtracking Geant4 libraries and the n-body event generator of ROOT libraries in order to provide a fast, realiable and complete MC tool to be used for nuclear physics experiments, with a particular focus on photo-nuclear processes. We discuss the results of the MC simulations performed in order to evaluate the effects of the electromagnetic background, the straggling of the emitted particles due to the target thickness and the resolution of the silicon detectors. Finally we present the preliminary results on some nuclear reactions involved in the p-process, which will be studied with ELISSA and the GBS at ELI-NP.

International audience; Studies on nuclear astrophysics, nuclear structure, and other interests have been performed using the radioactive-isotope (RI) beams at the low-energy RI beam separator CRIB, operated by Center for Nuclear Study (CNS), the University of Tokyo. A type of measurement to study astophysical reactions at CRIB is by the elastic resonant scattering with the thick-target method in inverse kinematics. An example is the α resonant scattering with 7Be beam, related to the astrophysical 7Be(α,γ) reactions, which is relevant in the hot p-p chain and νp-process in supernovae. Other α resonant scattering measurements with 30S, 10Be, 15O, and 18Ne beams have been performed at CRIB, using the thick-target method. There have also been measurements based on other experimental methods. The first Trojan horse method (THM) measurement using an RI beam has been performed at CRIB, to study the 18F(p, α)15O reaction at astrophysical energies via the three body reaction 2H(18F, α15O)n. The 18F(p, α)15O reaction rate is crucial to understand the 511-keV γ-ray production in nova explosion phenomena, and we successfully evaluated the reaction cross section at novae temperature and below experimentally for the first time.

The cosmological 7Li problem has been one of the big issues left in the standard Big-Bang nucleosynthesis (BBN) model. In order to determine the radiogenic 7Li abundance by the BBN, it is important to know the production and the destruction rate of 7Be rather than 7Li itself. We performed indirect measurements of the relevant neutron-induced reactions 7Be(n, p)7Li and 7Be(n, α)4He simultaneously by the Trojan Horse Method (THM) via the three-body reactions 7Be(d,7Lip)1H and 7Be(d, αα)1H. A 7Be radioactive-isotope (RI) beam at 3.16 MeV/u was produced at Center-for-Nuclear-Study RI Beam (CRIB) separator. The Q-value spectra shows the evidence of the three-body channels of interest. We confirmed that the THM was applicable to the present measurements by the momentum distributions of the spectator proton. Preliminary excitation functions are roughly consistent with the previous studies, moreover providing new data in the BBN energy range, and suggesting that new information about the 7Be(n, p1)7Li* contribution may be obtained by carrying out a further data analysis.

We discuss new results concerning the investigation of the 19F(p, α 0)16O reaction at very low energies (0.6-0.2 MeV). This reaction is important both in Nuclear Astrophysics, because it closes the CNOF cycle and it is an important fluorine destruction channel in hydrogen rich stellar environments, and in Nuclear Structure, because it allows to study the spectroscopy of the self-conjugated 20Ne compound nucleus. Despite its importance, very few direct data have been published at low energies in the literature. Our work allowed to deduce the S-factor down to ≈ 0.2 MeV and to point out the role played by broad resonances at low energies. The experimental S- factor is ≈1.5-2 times larger than non-resonant extrapolations reported by nacre with potentially important astrophysical consequences.

Photodisintegration reaction rates involving charged particles are relevant to the p-process nucleosynthesis that aims at explaining the production of stable neutron-deficient nuclides heavier than iron. In this study, considering the compound and pre-equilibrium reaction mechanisms, the cross sections and astrophysical rates of (γ,p) and (γ,α) reactions for about 3000 target nuclei with 10≤Z≤100 ranging from stable to proton dripline nuclei are computed. To study the sensitivity of the calculations to the optical model potentials (OMPs), both the phenomenological Woods-Saxon and the microscopic folding OMPs are taken into account. The systematic comparisons show that the reaction rates, especially for the (γ,α) reaction, are dramatically influenced by the OMPs. Thus, better determination of the OMP is crucial to reduce the uncertainties of the photodisintegration reaction rates involving charged particles. Meanwhile, a γ-beam facility at Extreme Light Infrastructure-Nuclear Physics (ELI-NP) is being developed which will open new opportunities to experimentally study the photodisintegration reactions of astrophysical interest. Considering both the important reactions identified by the nucleosynthesis studies and the purpose of complementing the experimental results for the reactions involving p nuclei, the measurements of six (γ,p) and eight (γ,α) reactions based on the γ-beam facility and the Extreme Light Infrastructure Silicon Strip Array (ELISSA) for the detection of charged particles at ELI-NP are proposed. Furthermore, the geant4 simulations on these (γ,p) and (γ,α) reactions are performed using the calculated cross sections and the features of the γ-beam facility and the ELISSA detector at ELI-NP. Simultaneously satisfying the minimum detectable limit of the experimental yield and the particle identification of protons and α particles, the minimum required energies of the γ beam to measure the six (γ,p) and eight (γ,α) reactions are estimated. It is shown that the direct measurements of these photonuclear reactions based on the γ-beam facility at ELI-NP within the Gamow windows at the typical temperature of T9=2.5 for the p-process are fairly feasible and promising. We believe that this pivotal work will guide the future photodisintegration experiments at ELI-NP. Furthermore, the expected experimental results will be used to constrain the OMPs of the charged particles, which can eventually reduce the uncertainties of the reaction rates for the p-process nucleosynthesis., SCOPUS: ar.j, info:eu-repo/semantics/published