Capture Cross Section Measurements of Long-lived Fission Products in the Resonance Neutron Energy Region

在目前的研究中，长寿命裂变产物（LLFPs）的中子俘获截面已被测量的中子时间关闭光的方法，使用12.7米的飞行路径和46 MeV的电子直线加速器（直线加速器）在研究反应堆研究所，京都大学（KURRI）。131我们测量了Tc-99、Rh-103、In-115、I-127、I-129、Cs-133和Pr-141的俘获截面。其中Tc-99和I-129是放射性物质，其余的是非放射性的稳定同位素。利用直线加速器飞行时间法和瞬发俘获γ射线测量，测量了几meV到几十keV的俘获截面。在俘获截面的测量中，采用了12块尺寸<12>为5cm × 5cm × 7.5cm的Bi_4Ge_3O_（BGO）晶体作为总能量吸收探测器，其上有一个通孔，通孔的直径为1.5cm，通孔的直径为1.5cm，通孔的直径为1. ...更多信息 将捕获样本设置在检测器组件的中心。入射中子能流/能谱已用^<10>B（n，α）标准截面监测，相对俘获截面已归一化为0.0253 eV的公知参考值。对于Rh-103、In-115和Cs-133的测量，在主共振峰处用饱和计数法获得了绝对俘获截面，并将上述俘获截面的早期实验和估算数据与目前的结果进行了比较。这些捕获截面并不总是满足数据的质量和数量，特别是在约10 eV以下的较低能量区域。对于某些核素或反应截面，没有实验数据，或目前的数据与早期的实验和评估数据之间存在差异。我们可以为研究或重新评估俘获截面提供有用的数据。

In the current study, neutron capture cross sections of longlived fission products (LLFPs) have been measured by the neutron time-off-light method using a 12.7 m flight path and a 46 MeV electron linear accelerator (linac) at the Research Reactor Institute, Kyoto University (KURRI). The earlier experimental and the evaluated nuclear data have been investigated by the current results obtainedWe have measured the capture cross sections of Tc-99, Rh-103, In-115, I-127, I-129, Cs-133, and Pr-141 as LLFPs. The nuclides of Tc-99 and I-129 are radioactive materials and the others are non-radio active stable isotopes. Making use of the linac TOF method and the prompt capture gammaray measurement, the capture cross sections have been measured from a few meV to several tens of keV. For the capture cross section measurement, an assembly of 12 pieces of Bi_4Ge_3O_<12> (BGO) scintillators (each size; 5cm x 5cm x 7.5cm) have been used as a total energy absorption detector, which has a through hole t … More o set the capture sample at the center of the detector assembly. The incident neutron energy flux/spectrum has been monitored with the ^<10>B(n, α ) standard cross section, and the relative capture cross section has been normalized to the well known reference value at 0.0253 eV. For the measurement of Rh-103, In-115 and Cs-133, the absolute capture cross section has been obtained by using a saturated count method at the major resonance peakThe earlier experimental and the evaluated data for the above capture cross sections have been compared with the current results. These capture cross sections have not been always satisfied with the data-quality and quantity, especially in the lower energy region below about 10 eV. For some nuclides or the reaction cross sections, no experimental data have been existed or the discrepancies have been seen between the current data and the earlier experimental and the evaluated data. We could provide the useful data for the investigation or the re-evaluation of the capture cross sections Less