在距离欧洲核子研究中心（CERN）n TOF中子源185 m的实验区，用在$^{154}$ Gd中富集到67 $\%$的金属钆样品，测量了$^{154}$ Gd在1 eV ~ 300 keV范围内的中子俘获截面。用四个C $_{6}$ D $_{6}$闪烁探测器进行的捕获测量得到了在GELINA飞行时间设施（JRC-Geel）进行的透射测量的补充，从而最大限度地减少了与样品成分有关的不确定性。推导了在所研究的温度范围内精确的麦克斯韦平均俘获截面（MACS），用于s过程核合成模拟。我们报告了在$kT=30$ keV下MACS的880（50）mb值，与文献中的值相比明显较低。新采用的$^{154}$ Gd（n，$γ$）截面减少观测和计算的太阳s-唯一的同位素丰度预测的s-过程核合成模型之间的差异。
英文摘要：
The neutron capture cross section of $^{154}$Gd was measured from 1 eV to 300 keV in the experimental area located 185 m from the CERN n\_TOF neutron spallation source, using a metallic sample of gadolinium, enriched to 67$\%$ in $^{154}$Gd. The capture measurement, performed with four C$_{6}$D$_{6}$ scintillation detectors, has been complemented by a transmission measurement performed at the GELINA time-of-flight facility (JRC-Geel), thus minimising the uncertainty related to sample composition. An accurate Maxwellian averaged capture cross section (MACS) was deduced over the temperature range of interest for s process nucleosynthesis modeling. We report a value of 880(50) mb for the MACS at $kT=30$ keV, significantly lower compared to values available in literature. The new adopted $^{154}$Gd(n,$γ$) cross section reduces the discrepancy between observed and calculated solar s-only isotopic abundances predicted by s-process nucleosynthesis models.
Measurement of cross sections and astrophysical S-factors for d(p,gamma)3He reaction at astrophysically relevant energies using a large volume LaBr3:Ce detector
We have performed the first direct measurement of the 83Rb(p,g) radiative capture reaction cross section in inverse kinematics using a radioactive beam of 83Rb at incident energies of 2.4 and 2.7 A MeV. The measured cross section at an effective relative kinetic energy of Ecm = 2.393 MeV, which lies within the relevant energy window for core collapse supernovae, is smaller than the prediction of statistical model calculations. This leads to the abundance of 84Sr produced in the astrophysical p process being higher than previously calculated. Moreover, the discrepancy of the present data with t…
14N(p,gamma)15O is one of the key reactions of nuclear astrophysics playing a role in various stellar processes and influencing energy generation of stars, stellar evolution and nucleosynthesis. For a reliable reaction rate calculation the low energy cross section of 14N(p,gamma)15O must be known with high accuracy. Owing to the unmeasurable low cross sections, theoretical calculations are unavoidable. High precision experimental cross section data are needed in a wide energy range in order to provide the necessary basis for low energy extrapolations. In the present work the total 14N(p,gamma)…
Investigation of alpha-induced reactions on 127I for the astrophysical gamma process
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One of the biggest questions in nuclear astrophysics is understanding where the elements come from and how they are made. This work focuses on the p process, a nucleosynthesis process that consists of a series of photodisintegration reactions responsible for producing stable isotopes on the proton-rich side of stability. These nuclei, known as the p nuclei, cannot be made through the well-known neutron-capture processes. Currently p-process models rely heavily on theory to provide the relevant reaction rates to predict the final p-nuclei abundances and more experimental data is needed. The pre…
Cross-sections for ${}^{nat}Pb(p,xn){}^{201-207}Bi$, ${}^{204}Pb(p,1-4n){}^{201-204}Bi$ and ${}^{206}Pb(p,3n){}^{204}Bi$ reactions have been determined in the astrophysical energy range $20-30 \, MeV$. The analysis were performed by $γ$-spectroscopy associated with half-lives measurements. The results were compared with previously experimental data, when available, and with theoretical calculations performed using TALYS code. We report a possible new $γ$ transition from ${}^{204m}{Pb}$ and other theoretical discrepancies, probably due overestimation of the Coulomb barrier and neutron binding e…
Concurrent application of ANC and THM to assess the $^{13}{\rm C}(α,n)^{16}{\rm O}$ absolute cross section at astrophysical energies and possible consequences for neutron production in low-mass AGB stars
The synthesis of heavy, proton rich isotopes is a poorly understood astrophysical process. Thermonuclear (type Ia) supernova explosions are among the suggested sites and the abundance of some isotopes present in the early solar system may be used to test the models. 92Nb is such an isotope and one of the reactions playing a role in its synthesis is 91Zr(p,gamma)92Nb. As no experimental cross sections were available for this reaction so far, nucleosynthesis models had to solely rely on theoretical calculations. In the present work the cross section of 91Zr(p,gamma)92mNb has been measured at ast…
We have measured the cross section of the $^{83}$Rb(p,$γ)^{84}$Sr radiative capture reaction in inverse kinematics using a radioactive beam of $^{83}$Rb at incident energies of 2.4 and $2.7 A$ MeV. Prior to the radioactive beam measurement, the $^{84}$Kr(p,$γ)^{85}$Rb radiative capture reaction was measured in inverse kinematics using a stable beam of $^{84}$Kr at an incident energy of $2.7 A$ MeV. The effective relative kinetic energies of these measurements lie within the relevant energy window for the $γ$ process in supernovae. The central values of the measured partial cross sections of bo…
Microscopic description of $^{12}$C+$^{12,13}$C fusion reactions at nuclear astrophysical energies
Department of Physics, Kyoto University（京都大学）；Institute for Liberal Arts and Sciences, Kyoto University（京都大学人文学部）；RIKEN Nishina Center for Accelerator-based Science, RIKEN（理化学研究所仁科加速器科学中心）；Nuclear Data Center, Japan Atomic Energy Agency（日本原子力机构核数据中心）
Nuclear reactions involving alpha particles play an important role in various astrophysical processes such as the gamma-process of heavy element nucleosynthesis. The poorly known low-energy alpha-nucleus optical (AOMP) potential is a key parameter to estimate the rates of these reactions. The AOMP can be tested by measuring the cross section of alpha-scattering as well as alpha-induced reactions. Low energy elastic alpha-scattering on 144Sm has recently been measured with high precision. The aim of the present work was to complement that work by measuring the (a,n) cross sections on 144Sm at l…
On the sensitivity of extracting the astrophysical cross section factor of the 12C(a,g) reaction from existing data [Comment on Schuermann et al. Phys. Lett. B711(2012)35]
