论文标题
$^{118} $ sn的$γ$射线的角度分布
Angular distribution of $γ$ rays from the p-wave resonance of $^{118}$Sn
论文作者
论文摘要
$^{117} {\ rm sn}（n，γ）$反应的中子能量依赖性角度分布是用锗检测器和脉冲中子束测量的。在$γ$ ray的排放中清楚地观察到了角度分布，能量为9327 keV，这对应于从$^{117} {\ rm sn}+n $的中子共振到$^{118} {\ rm sn} $的基础状态。角分布会导致角度依赖性的不对称共振形状。不对称$ a _ {\ rm lh} $定义为$（n _ {\ rm l} -n _ {\ rm h}）/（n _ {\ rm l}+n _ {\ rm l}+n _ {\ rm h}）$，wher中子共振的低能量区域和高能区域。 We found that the $A_{\rm LH}$ has the angular dependence of $(A \cos θ_γ+B)$, where $θ_γ$ is the $γ$-ray emission angle with respect to the incident neutron momentum, with $A=0.394 \pm 0.073$ and $B = 0.118 \pm 0.029$ in the 1.33 eV p-wave resonance.
The neutron energy-dependent angular distribution of $γ$ rays from $^{117}{\rm Sn}(n,γ)$ reaction was measured with germanium detectors and a pulsed neutron beam. The angular distribution was clearly observed in $γ$-ray emissions with an energy of 9327 keV which corresponds to the transition from a neutron resonance of $^{117}{\rm Sn}+n$ to the ground state of $^{118}{\rm Sn}$. The angular distribution causes an angular-dependent asymmetric resonance shape. An asymmetry $A_{\rm LH}$ was defined as $(N_{\rm L}-N_{\rm H})/(N_{\rm L}+N_{\rm H})$, where $N_{\rm L}$ and $N_{\rm H}$ are integrated values for lower- and higher-energy regions of a neutron resonance, respectively. We found that the $A_{\rm LH}$ has the angular dependence of $(A \cos θ_γ+B)$, where $θ_γ$ is the $γ$-ray emission angle with respect to the incident neutron momentum, with $A=0.394 \pm 0.073$ and $B = 0.118 \pm 0.029$ in the 1.33 eV p-wave resonance.
