AI 中文总结
本研究对采用平行板几何结构的$^{238}$U裂变室进行特性表征，验证其效率、线性度及抗环境干扰能力，确认其可作为SPARC中子诊断套件的可靠聚变功率测量方案。
AI 中文摘要
SPARC托卡马克将采用基于$^{238}$U的裂变室（FC）来监测高性能氘-氚（DT）等离子体运行，覆盖中子产额率范围从约$10^{15}$到大于$10^{19}$ n/s。本工作验证了$^{238}$U FC的设计，该设计采用平行板探测器几何结构和含硼聚乙烯准直器，以优先选择未散射的DD和DT聚变中子。通过DD和DT中子发生器的实验测试证实了供应商指定的效率，并展示了出色的探测器线性度，测量的计数率与OpenMC中子学模拟结果吻合良好。进一步的表征确认了$^{238}$U FC对SPARC相关环境挑战的鲁棒性，包括高达14 mT的杂散磁场以及与约30米长电缆走线相关的可能信号退化风险。这些结果证实，在间接中子屏蔽以及适当的脉冲高度阈值的支持下，$^{238}$U FC为作为SPARC中子诊断套件一部分的聚变功率测量提供了可靠的解决方案。
英文摘要
The SPARC tokamak will employ $^{238}$U-based fission chambers (FCs) to monitor high-performance deuterium-tritium (DT) plasma operations, spanning neutron yield rates from ${\sim}10^{15}$ to ${>}10^{19}$ n/s. This work validates the $^{238}$U FC design, which utilizes a parallel-plate detector geometry and borated polyethylene collimation to prioritize unscattered DD and DT fusion neutrons. Experimental testing with both DD and DT neutron generators corroborates vendor-specified efficiencies and demonstrates excellent detector linearity, with measured count rates showing good agreement with OpenMC neutronics simulations. Further characterization confirms the $^{238}$U FC's robustness against SPARC-relevant environmental challenges, including stray magnetic fields up to 14 mT and possible signal degradation risks associated with $\sim$30 m long cable runs. These results confirm that the $^{238}$U FC, supported by indirect neutron shielding as well as appropriate pulse height thresholds, provides a reliable solution for fusion power measurements as part of the SPARC neutron diagnostics suite.
