发表机构
National Institute for Physics and Nuclear Engineering, Horia Hulubei (IFIN-HH); Institut d’Astronomie et d’Astrophysique, Université Libre de Bruxelles; Lomonosov Moscow State University; Institute of Nuclear Physics Polish Academy of Sciences; Shanghai Advanced Research Institute, Chinese Academy of Sciences; Institut für Kernphysik, Technische Universität Darmstadt（霍里亚·胡利贝伊核物理与核工程国家研究所; 布鲁塞尔自由大学天体物理学与天文学研究所; 莫斯科罗蒙诺索夫国立大学; 波兰科学院核物理研究所; 中国科学院上海高等研究院; 达姆施塔特工业大学核物理研究所）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究利用NewSUBARU的准单色γ射线束测量了$^{165}$Ho和$^{169}$Tm的光中子反应截面，提取了GDR参数、四极矩并检验了统计模型，发现20-25 MeV高能结构支持巨四极共振预测。
AI 中文摘要
利用日本NewSUBARU设施提供的准单色激光康普顿散射γ射线束，研究了从中子发射阈值附近到约40 MeV（远高于巨偶极共振（GDR）区）的形变核$^{165}$Ho和$^{169}$Tm的光中子反应。采用高且平坦效率的慢化$^3$He计数器阵列进行中子探测，并采用相关的中子多重性分类方法提取$(\gamma,\\,1nX)$、$(\gamma,\\,2nX)$、$(\gamma,\\,3nX)$和$(\gamma,\\,4nX)$反应截面及平均中子发射能量。将本工作的$^{165}$Ho截面与现有数据进行了比较，揭示了与Saclay多重性分类结果的差异，以及与Livermore结果相比总体10%的强度差异。$^{169}$Tm没有其他数据。通过拟合本工作的$\sigma(\gamma,\\,Sn)$数据，并针对实验未观测到的仅带电粒子反应的缺失贡献进行调整，提取了基于唯象Lorentzian模型的GDR参数。对于两个核，我们观察到20-25 MeV处的高能结构，与巨四极共振KMFR预测相符。基于本工作第一和第二GDR峰的质心能量，流体动力学模型预测$^{165}$Ho和$^{169}$Tm基态的内禀电四极矩分别为+7.00(34)~b和+7.38(28)~b。将本工作的实验激发函数和光中子能量与统计模型计算进行了比较。使用EMPIRE代码，我们对光子强度函数和核能级密度的唯象模型进行了敏感性测试。使用TALYS代码，利用微观核能级密度模型重现了本工作的实验$(\gamma,\\,inX)$截面和平均中子能量。
英文摘要
Photoneutron reactions were investigated for the deformed $^{165}$Ho and $^{169}$Tm nuclei from the vicinity of the neutron emission threshold up to $\sim$40~MeV, well above the giant dipole resonance (GDR) region, using quasimonochromatic laser Compton scattering $γ$-ray beams provided at the NewSUBARU facility, Japan. A high-and-flat efficiency moderated array of $^3$He counters was used for the neutron detection and an associated neutron multiplicity sorting method for extracting the $(γ,\,1nX)$, $(γ,\,2nX)$, $(γ,\,3nX)$ and $(γ,\,4nX)$ reaction cross sections and average neutron emission energies. The present $^{165}$Ho cross sections were compared to existing data, revealing discrepancies with the Saclay multiplicity sorting results and an overall 10$\%$ strength difference with the Livermore ones. There are no other data for $^{169}$Tm. GDR parameters based on phenomenological Lorentzian models were extracted by fitting the present $σ(γ,\,Sn)$ data with adjustments for the missing contribution of charged-particle-only reactions not observed experimentally. For both nuclei we observed high energy structures at 20-25~MeV, matching giant quadrupole resonance KMFR predictions. Based on the present centroid energies of the first and second GDR peaks, hydrodynamic model predictions gave intrinsic electric quadrupole moments of +7.00(34)~b and +7.38(28)~b for the ground states of $^{165}$Ho and $^{169}$Tm, respectively. The present experimental excitation functions and photoneutron energies were compared to statistical model calculations. Using the EMPIRE code, we performed a sensitivity test to phenomenological models of photon strength functions and nuclear level densities. The TALYS code was used to reproduce the present experimental $(γ,\,inX)$ cross sections and average neutron energies using microscopic nuclear level density models.
