液氮、液氦和液氩中直流电气击穿分布的对比测量
Comparative measurements of DC electrical breakdown distributions in liquid nitrogen, liquid helium, and liquid argon
AI总结：
该研究通过通用实验装置对比液氮、液氦、液氩的直流击穿分布，揭示了三者击穿特性的差异及影响机制，为低温液体击穿强度的对比研究提供了框架。
AI中文摘要：
我们采用通用的低温恒温器、电极组件、电压斜坡协议和分析程序，对液氮、液氦和液氩中的直流电气击穿开展对比研究。该通用实验配置可最大程度减少通常使低温液体间对比复杂化的系统差异，包括电极几何形状、受应力面积、表面光洁度和间隙间距的变化。对于每种液体，击穿被表征为统计分布而非单一特征电压，从而可研究该过程的随机特性。测量在接近饱和蒸气压和适度加压两种条件下进行，以评估气泡形成及相关热力学效应的影响。液氩表现出非稳态“启动”行为，击穿电压随重复放电而升高，这与局部杂质环境或电极表面状态的演变一致。接近饱和蒸气压时，液氦呈现双峰击穿分布，其中低场成分与气泡介导过程一致。液氮的击穿场强高于液氩，且与加压液氦中测得的场强相当，处于与表面状态相关的观测逐次运行变化范围内。总体而言，这些结果支持一种对比框架，其中击穿强度既反映了抗气泡形成的热力学稳定性，也反映了主导负电荷载流子的输运特性。
英文摘要：
We present a comparative study of DC electrical breakdown in liquid nitrogen, liquid helium, and liquid argon using a common cryostat, electrode assembly, voltage-ramp protocol, and analysis procedure. This common experimental configuration minimizes systematic differences that often complicate comparisons among cryogenic liquids, including variations in electrode geometry, stressed area, surface finish, and gap spacing. For each liquid, breakdown was characterized as a statistical distribution rather than by a single characteristic voltage, allowing the stochastic nature of the process to be examined. Measurements were performed both near saturated vapor pressure and under modest pressurization to assess the influence of bubble formation and related thermodynamic effects. Liquid argon exhibited a non-stationary "turn-on" behavior, with breakdown voltage increasing over repeated discharges, consistent with evolution of the local impurity environment or electrode surface state. Near saturated vapor pressure, liquid helium showed a bimodal breakdown distribution, with a lower-field component consistent with bubble-mediated processes. Liquid nitrogen exhibited higher breakdown fields than liquid argon and fields comparable to those measured in pressurized liquid helium, within the observed run-to-run variation associated with surface state. Taken together, these results support a comparative framework in which breakdown strength reflects both thermodynamic stability against bubble formation and the transport properties of the dominant negative charge carrier.
