Abstract Two isotopically-characterized targets of high-purity (99.84±0.03%) 235U-oxide and a neutron dosimetry package were exposed to a pulsed neutron irradiation using the Godiva critical assembly at the National Criticality Experiments Research Center. Following irradiation, the fissioned targets were counted with a broad-energy germanium detector. Estimates of the total fissions for each target were made using measurements of well-known fission products. The total fission values were then used to measure the fission yields of 21 fission products with half-lives between 636 and 119,700 seconds. Mean values of seventeen of the measured fission products fell within the 95% confidence level of the Evaluated Nuclear Data Files VII.1/b (ENDF/B-VII.1) using the larger of the two uncertainties: 84gBr, 89Rb, 91Sr, 93Y, 97Zr, 101Mo, 105Ru, 128Sn, 129Sb, 130gSb, 131Sb, 131mTe, 133I, 135I, 141Ba, 142Ba, and 142La. Seven isotopes were measured to better precision than is listed in the ENDF/B-VII.1 database: 89Rb, 93Y, 128Sn, 129Sb, 130gSb, 131mTe, and 133I. Four of the measured isotopes were found to be statistically different from the ENDF/B-VII.1 database: 94Y, 134Te, 134I, and 138Xe. Two of the isotopic analyses conducted in this paper fit the parent and daughter data simultaneously. The parent-daughter pairs measured in this way were the 134Te/I and 142Ba/La pairs. The fission yield results obtained in this way are unique, especially for 134I, because the parent and daughter half-lives are so close. Given the limited number of direct measurements of the 134Te/I pair from fast neutron induced fission and the seemingly high estimate for 134Te from previous work, it is likely that the value in this paper is more accurate; however, additional measurements of this pair are needed to validate this assertion.

中文翻译：

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使用 235U 上的裂变谱中子改进累积裂变产率测量

摘要 在国家临界性实验研究中心，使用 Godiva 临界组件将两个同位素表征的高纯度 (99.84±0.03%) 235U 氧化物靶和中子剂量测定包暴露于脉冲中子辐照下。辐照后，裂变目标用广能锗探测器计数。使用众所周知的裂变产物的测量值对每个目标的总裂变进行估计。然后使用总裂变值测量半衰期在 636 到 119,700 秒之间的 21 种裂变产物的裂变产额。17 个测量裂变产物的平均值落在评估核数据文件 VII.1/b (ENDF/B-VII.1) 的 95% 置信水平内，使用两个不确定性中的较大者：84gBr、89Rb、91Sr、 93Y、97Zr、101Mo、105Ru、128Sn、129Sb、130gSb、131Sb、131mTe、133I、135I、141Ba、142Ba 和 142La。七种同位素的测量精度高于 ENDF/B-VII.1 数据库中所列的同位素：89Rb、93Y、128Sn、129Sb、130gSb、131mTe 和 133I。发现四种测量的同位素与 ENDF/B-VII.1 数据库有统计学差异：94Y、134Te、134I 和 138Xe。本文中进行的两项同位素分析同时拟合父子数据。以这种方式测量的亲子对是 134Te/I 和 142Ba/La 对。以这种方式获得的裂变产额结果是独一无二的，尤其是 134I，因为父子半衰期非常接近。鉴于对来自快中子诱发裂变的 134Te/I 对的直接测量数量有限，并且先前工作对 134Te 的估计似乎很高，很可能本文中的值更准确；然而，需要对这一对进行额外的测量来验证这个断言。