论文标题
$^{69,71} $ ga
Stellar $s$-process neutron capture cross sections of $^{69,71}$Ga
论文作者
论文摘要
稳定的同位素，$^{69,71} $ ga，主要由巨大的恒星中的弱慢（$ s $）过程产生。我们在此报告$^{69,71} $ ga $（n，γ）$反应的$^{69,71} $ ga $（n，γ）$反应的截面的测量值。实验是通过激活技术使用高强度（$ 3-5 \ times10^{10} $ n/s）的，准 - 麦克斯韦的中子束，与$ kt \ $ kt \ 40 kev的恒星$ s $ s $ sucleosynthesis的条件紧密地模仿了恒星$ s $ s $ s $ s的核合成条件。中子场是由$ e_p = 1925 $ keV（2-3 kW的束功率）的MA质子束从SOREQ应用研究加速器设施（SARAF）产生的，轰击了液叶靶（LiLIT）。 473毫克的GA $ _2 $ o $ _3 $的天然同位素组合物在Lilit Neutron领域激活，并且通过$γ$ -SpectRometry计数$^{70,72} $ ga的活动测量，具有高纯化的Germanium检测器。 $ kt $ = 30 keV的麦克斯韦式横截面的$^{69} $ ga和$^{71} $ ga在这项工作中确定的是136（8）MB和105（7）MB，与以前的实验值非常吻合。讨论了测量的天体物理意义。
The stable gallium isotopes, $^{69,71}$Ga, are mostly produced by the weak slow ($s$) process in massive stars. We report here on measurements of astrophysically-relevant neutron capture cross sections of the $^{69,71}$Ga$(n,γ)$ reactions. The experiments were performed by the activation technique using a high-intensity ($3-5\times10^{10}$ n/s), quasi-Maxwellian neutron beam that closely mimics conditions of stellar $s$-process nucleosynthesis at $kT \approx$ 40 keV. The neutron field was produced by a mA proton beam at $E_p=1925$ keV (beam power of 2-3 kW) from the Soreq Applied Research Accelerator Facility (SARAF), bombarding the Liquid-Lithium Target (LiLiT). A 473 mg sample of Ga$_2$O$_3$ of natural isotopic composition was activated in the LiLiT neutron field and the activities of $^{70,72}$Ga were measured by decay counting via $γ$-spectrometry with a high-purity germanium detector. The Maxwellian-averaged cross sections at $kT$ = 30 keV of $^{69}$Ga and $^{71}$Ga determined in this work are 136(8) mb and 105(7) mb, respectively, in good agreement with previous experimental values. Astrophysical implications of the measurements are discussed.
