{Background}: Most of the heavier $p$ isotopes are believed to be produced in the $\gamma$ process whose reaction path crucially depends on the proton- and $\alpha$-particle penetrability at sub-Coulomb energies. Both nuclei of the samarium p-process chronometer, and , are produced in the $\gamma$-process and their initial abundance ratio is very sensitive to the ($\gamma$,$n$) and ($\gamma$,$\alpha$) branching ratio on . The ($\gamma$,$\alpha$) reaction rate has been measured roughly 20 years ago by means of the activation technique and its surprising results triggered adjustments to the global low-energy $\alpha$+nucleus optical-model potentials. {Purpose}: We want to take advantage of modern $\alpha$-particle spectroscopy techniques in order to constrain the controversial previous results on the ($\gamma$,$\alpha$) reaction rate. {Method:} The ($\gamma$,$\alpha$) reaction rate has been determined by measuring the cross section of the reverse reaction ($\alpha$,$\gamma$) applying the activation technique to the $\alpha$-decay of . Targets have been irradiated at the cyclotron of the Physikalisch-Technische Bundesanstalt in Braunschweig, Germany. The $\alpha$-particle spectroscopy has been carried out with a state-of-the-art low-background ionization chamber of the Technische Universit"at Dresden, Germany. {Results}: Cross sections for the ($\alpha$,$\gamma$) reaction have been measured between and with much higher precision than in the previous measurement. The results agree with earlier results within their uncertainties. The statistical-model analysis has been carried out using the Talys code on the basis of the latest parameterizations of $\alpha$-OMPs. The best reproduction of the experimental results within the statistical model have been used to calculate the reaction rates. {Conclusion:} The values presented here suggest a steeper increase in the astrophysical S-factor towards lower center-of-mass energies. Different parameterizations of the $\alpha$-OMP were able to describe the experimental values sufficiently. Further measurements at energies below are suggested.

中文翻译：

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γ过程中144Sm（α，γ）148Gd反应速率的新测量

{背景}：大多数较重 $p$ 同位素被认为是在 $\gamma$ 反应路径关键取决于质子和 $\alpha$-亚库仑能量下的粒子渗透性。p p过程计时码表和的两个核都是在$\gamma$-过程及其初始丰度比对（$\gamma$，$ñ$）和（$\gamma$，$\alpha$）上的分支比。（$\gamma$，$\alpha$）大约20年前已经通过活化技术测量了反应速率，其惊人的结果引发了对全球低能耗的调整。 $\alpha$+核光学模型电位。{目的}：我们想利用现代$\alpha$粒子光谱技术，以便将先前有争议的结果限制在（$\gamma$，$\alpha$） 反应速度。{方法：}（$\gamma$，$\alpha$）反应速率已通过测量逆反应的横截面（$\alpha$，$\gamma$）将激活技术应用于 $\alpha$-的衰减。目标已在德国不伦瑞克的Physikalisch-Technische Bundesanstalt的回旋加速器上辐照过。的$\alpha$粒子光谱学是使用德国德累斯顿工业大学的最新低背景电离室进行的。{结果} ：($\alpha$，$\gamma$）反应之间进行了测量，并且比以前的测量精度要高得多。结果与之前的结果在不确定性范围内一致。统计模型分析是根据最新的参数设置，使用Talys代码进行的$\alpha$-OMP。统计模型内实验结果的最佳再现已用于计算反应速率。{结论：}此处给出的值表明，天文学的S因子朝着较低的质心能量急剧增加。的不同参数化$\alpha$-OMP能够充分描述实验值。建议在以下能量处进一步测量。