Samples of a commercially available polyphenyl ether (PPE) oil are irradiated in the mixed neutron and gamma radiation field of the Pavia TRIGA Mark II reactor, at irradiation doses ranging from 0.78 MGy to 7.8 MGy. The oil is a nuclear grade product, whose radiation resistance reported in the product specification is based on cobalt-60 gamma irradiation data. The collection of additional data in a nuclear reactor radiation field performed in the present work, is motivated by the need to use this oil in neutron-rich environments such as targets and accelerators.

The post-irradiation characterization of the oil samples here reported includes viscosity measurements, total acid number (TAN), Fourier transform infrared spectroscopy (FT-IR), gas chromatography (GC), gel permeation chromatography (GPC) and nuclear magnetic resonance (NMR) spectroscopy.

The presented results evidence a remarkable increase of kinetic viscosity with the absorbed dose. Differences in the radiation-induced viscosity increase are observed comparing the data collected in mixed neutron and gamma radiation with the previous ones collected in cobalt-60 gamma radiation. This result emphasizes the need of further studies on the dependence of the radiation damage on different radiation environments. A negligible increase of TAN is reported. The FT-IR, GC, GPC and NMR show progressive polymerization with increasing dose. The increasing molecular size is in line with the viscosity data presented.

在Pavia TRIGA Mark II反应器的混合中子和γ辐射场中以0.78 MGy至7.8 MGy的辐照剂量辐照可商购的聚苯醚（PPE）油样品。该油是核级产品，其产品规格中报告的抗辐射性基于60钴γ辐照数据。由于需要在富含中子的环境（例如目标和加速器）中使用这种油，因此激发了本工作中在核反应堆辐射场中收集其他数据的动机。

这里报道的油样品的辐照后表征包括粘度测量，总酸值（TAN），傅立叶变换红外光谱（FT-IR），气相色谱（GC），凝胶渗透色谱（GPC）和核磁共振（NMR） ）光谱学。

提出的结果证明，随着吸收剂量的增加，运动粘度显着增加。通过比较在混合中子和伽马射线中收集的数据与在钴60伽马射线中收集的先前数据，可以观察到由辐射引起的粘度增加的差异。该结果强调需要进一步研究辐射损伤对不同辐射环境的依赖性。据报道，TAN的增加可忽略不计。FT-IR，GC，GPC和NMR显示随着剂量的增加逐渐进行聚合。分子大小的增加与给出的粘度数据一致。