A new study of $^{10}$B(p,$α$)$^{7}$Be reaction at low energies
A. Caciolli, R. Depalo, C. Broggini, M. La Cognata, L. Lamia, R. Menegazzo, L. Mou, S. M. R. Puglia, V. Rigato, S. Romano, C. Rossi Alvarez, M. L. Sergi, C. Spitaleri, A. Tumino
The $^{10}$B(p,$α$)$^{7}$Be reaction is of great interest since it has many applications in different fields of research such as nuclear astrophysics, nuclear physics, and models of new reactors for clean energy generation. This reaction has been studied at the AN2000 accelerator of the INFN National Laboratories of Legnaro (LNL). The total cross section has been measured in a wide energy range (250 $-$ 1182 keV) by using the activation method. The decays of the $^7$Be nuclei produced by the reaction were measured at the low counting facility of LNL by using two fully shielded high-purity germanium detectors. The present dataset shows a large discrepancy with respect to one of the previous data at the same energies and reduces the total uncertainty to the level of 6\%. An R-matrix calculation has been performed on the present data using the parameters from previous Trojan Horse measurements for the 10 and 500 keV resonances. The present data do not lay on the R-matrix fit in one point suggesting the existence of a $^{11}$C level not observed yet. Further nuclear investigations are needed to confirm this hypothesis.
Mechanism of nuclear reactions on 197Au induced by 11B ions at energies above Coulomb barrier was studied by induced-activity method and gamma-spectroscopy. The cross sections of the reaction fragments from 197Au induced by 11B ions were measured at bombarding energies 137.5 and 255.5 MeV. The fission process was investigated by using multimodal fission approach at the energy 137.5 MeV, and pure symmetric distribution at 255.5 MeV. It was observed that the transferred linear momentum provides the information on the initial projectile-target information. The fissility for both fission reactions…
In nuclear astrophysics, the experimental scenario is still unclear for BBN relevant energies from 30-300 keV. Here, we report our measurements of cross section and astrophysical S(E) factor for pd capture reaction using proton beam energies 66 keV, 116 keV and 166 keV. Realistic GEANT4 simulations were carried out in order to estimate the energy dependent efficiency of the detector. The measured cross section and astrophysical S(E) factor for three new incident proton energies are found to be in good agreement, within the errors, with the values reported in the literature.
Fusion cross sections for 6,7Li + 24Mg reactions at energies below and above the barrier
用特征γ射线法测量了6，7 Li +24 Mg反应的熔合截面，能量范围从低于库仑势垒到远高于库仑势垒。从这两个系统的γ射线截面得到的熔合截面与低能时的总反应截面吻合得很好。熔合截面随能量增加而减小的现象与其它通道，特别是碎裂通道随轰击能量增加而打开的事实相一致。这表明，在屏障之上或之下，这些系统的融合截面既没有抑制也没有增强。由熔合截面导出的临界角动量（lcr）具有与其它Li诱导反应相似的能量依赖性。
Background: alpha-nucleus potentials play an essential role for the calculation of alpha-induced reaction cross sections at low energies in the statistical model... Purpose: The present work studies the total reaction cross section sigma_reac of alpha-induced reactions at low energies which can be determined from the elastic scattering angular distribution or from the sum over the cross sections of all open non-elastic channels. Method: Elastic and inelastic 64Zn(a,a)64Zn angular distributions were measured at two energies around the Coulomb barrier at 12.1 MeV and 16.1 MeV. Reaction cross sec…
The cross sections for (γ,xn) reactions at 30 MeV and 40 MeV bremsstrahlung end-point energies on natural rhenium (natRe) targets have been measured by the activation and the off-line γ-ray spectrometric techniques using a High Purity Germanium detector (HPGe). The measured natRe(γ,xn) reaction cross sections were compared to the theoretically calculated cross sections using TALYS 1.9 and EMPIRE 3.2 computer codes. The measurements allowed the determination of the Isomeric Cross section Ratios (ICR) for the 184m,g Re and 182m,gRe isomeric pairs. In addition, we have determined a semi-empirical…
Photonuclear reactions on stable isotopes of cadmium and tellurium at bremsstrahlung end-point energies of 10-23 MeV
Joint Institute for Nuclear Research（联合核研究所）；Institute of Nuclear Physics of the Academy of Sciences of the Republic of Uzbekistan（乌兹别克斯坦共和国科学院核物理研究所）；Skobeltsyn Institute of Nuclear Physics of Lomonosov Moscow State University（莫斯科国立大学斯科别尔琴核物理研究所）；Faculty of Physics of Lomonosov Moscow State University（莫斯科国立大学物理系）；Bogoliubov Laboratory of Theoretical Physics of Joint Institute for Nuclear Research（联合核研究所博戈留博夫理论物理实验室）；Dzhelepov Laboratory of Nuclear Problems of Joint Institute for Nuclear Research（联合核研究所杰列波夫核问题实验室）；Institute of Nuclear Physics, Almaty（阿拉木图核物理研究所）
Differential cross sections $^4$He({$γ$,p})$^3$H and $^4$He({$γ$,n})$^3$He reactions in the range of the photon energies up to the threshold of the meson production
Carbon and oxygen burning reactions, in particular, $^{12}$C+$^{12}$C fusion, are important for the understanding and interpretation of the late phases of stellar evolution as well as the ignition and nucleosynthesis in cataclysmic binary systems such as type Ia supernovae and x-ray superbursts. A new measurement of this reaction has been performed at the University of Notre Dame using particle-$γ$ coincidence techniques with SAND (a silicon detector array) at the high-intensity 5U Pelletron accelerator. New results for $^{12}$C+$^{12}$C fusion at low energies relevant to nuclear astrophysics …
\item[Background]Heavy-ion reactions from barrier up to Fermi energy. \item[Purpose]Reaction and fusion cross sections determination. Fusion reactions induced by $^{129}Xe$ projectiles on $^{nat}Sn$ targets for energies ranging from $8$ A.MeV to $35$ A.MeV were measured with the INDRA $4π$-array.\\ The evaluation of the fusion/incomplete fusion cross sections for the incident energies from 8 to 35 A.MeV is the main purpose of this paper. \item[Method] The reaction cross sections are evaluated for each beam energy thanks to INDRA $4π$-array. The events are also sorted in order to focus the stud…
Statistical model calculations have to be used for the determination of reaction rates in large-scale reaction networks for heavy-element nucleosynthesis. A basic ingredient of such a calculation is the a-nucleus optical model potential. Several different parameter sets are available in literature, but their predictions of a-induced reaction rates vary widely, sometimes even exceeding one order of magnitude. This paper presents the result of a-induced reaction cross-section measurements on gold which could be carried out for the first time very close to the astrophysically relevant energy regi…
Reactions involving the group of nuclei commonly known as p nuclei are part of the nucleosynthetic mechanisms at astrophysical sites. The $^{113}$In nucleus is such a case with several open questions regarding its origin at extreme stellar environments. In this work, the experimental study of the cross sections of the radiative proton-capture reaction $^{112}$Cd(p,$γ$)$^{113}$In is attempted for the first time at energies lying inside the Gamow window with an isotopically enriched $^{112}$Cd target. Two different techniques, the in-beam $γ$-ray spectroscopy and the activation method, have been…
Nuclear multifragmentation is an important phenomenon, the study of which can throw light on reaction mechanism in heavy ion collisions at intermediate and high energies. Based on statistical and dynamical model studies, this thesis is concentrated mainly on, the following three aspects of nuclear multifragmentation reactions namely (i) production of exotic nuclei which are normally not available in the laboratory (ii) nuclear symmetry energy from heavy ion collisions at intermediate energies and (iii) Nuclear liquid-gas phase transition. In addition to these equivalence of statistical ensembl…
Correlations and clustering are of great importance in the study of the Nuclear Equation of State. Information on these items/aspects can be obtained using Heavy-Ion reactions which are described by dynamical theories. We propose a dataset that will be useful for improving the description of light cluster production in transport model approaches. The dataset combines published and new data and is presented in a form that allows direct comparison of the experiment with theoretical predictions. The dataset is ranging in bombarding energy from 32 to 1930 A MeV. In constructing this dataset we put…
New experimental results for the elastic scattering of 6He on 64Zn at incident energies of 15.0 and 18.0 MeV and 4He at 17.5 MeV along with results already published at 10.0 and 13.6 MeV, are presented. Elastic and alpha experimental cross sections are compared with coupled-reaction-channel, continuum-discretized coupledchannel, and DWBA inclusive-breakup models. The large yield of alpha particles observed at all measured energies can be explained by considering a nonelastic breakup mechanism.
A setup designed to study photonuclear reactions at astrophysical energies - an active target Time Projection Chamber was developed and constructed at the Faculty of Physics, University of Warsaw. The device was successfully employed in two experiments at the Institute of Nuclear Physics Polish Academy of Sciences in Cracow, in which γ- and neutron-induced reactions with CO2 gas target were measured. The reaction products were detected and their momenta reconstructed. Preliminary results are shown.
The hindrance phenomenon of heavy-ion fusion cross sections at deep subbarrier energies often accompanies a maximum of an astrophysical $S$ factor at a threshold energy for fusion hindrance. We argue that this phenomenon can naturally be explained when the fusion excitation function is fitted with two potentials, with a larger (smaller) logarithmic slope at energies lower (higher) than the threshold energy. This analysis clearly suggests that the astrophysical $S$ factor provides a convenient tool to analyze the deep subbarrier hindrance phenomenon, even though the $S$ factor may have a strong…
The scarce data systematics and complexity of deuteron interactions demand the update of both the experimental database and theoretical frame of deuteron activation cross sections. Various reactions induced by neutrons and protons following the deuteron breakup (BU) should be also taken into account. On the other hand, deuteron reaction cross sections recommended recently for high-priority elements are still based on data fit without predictive power. Purpose: Accurate new measurements of low-energy deuteron-induced reaction cross sections for monoisotopic (55Mn) natural manganese target enhan…
Coupled-channels description of multinucleon transfer and fusion reactions at energies near and far below the Coulomb barrier
我们研究重离子多核子转移反应使用耦合通道形式主义。我们首先使用半经典近似，并表明入口和对传输通道之间的直接耦合，提高了适合的实验一个和两个中子转移截面的40 Ca +96 Zr和60 Ni +116 Sn系统。然后，我们讨论的微扰方法的有效性，并突出高阶项的效果。吸收的影响也研究了库仑势垒周围的能量。最后，我们使用量子耦合通道的方法来实现的融合截面和转移概率的40 Ca +96 Zr反应的同时描述。我们发现，集体激发态的耦合对库仑势垒附近的转移几率有显著的影响。
The 27Al(p,a)24Mg reaction, which drives the destruction of 27Al and the production of 24Mg in stellar hydrogen burning, has been investigated via the Trojan Horse Method (THM) by measuring the 2H(27Al,a24Mg)n three-body reaction. The experiment covered a broad energy range (-0.5 MeV < E_cm < 1.5 MeV), aiming to investigate those of interest for astrophysics.The results confirm the THM as a valuable technique for the experimental study of fusion reactions at very low energies and suggest the presence of a rich pattern of resonances in the energy region close to the Gamow window of stellar hydr…
