Laser Entrance Hole Window Burst and Pressure Deflections at Cryogenic Temperature
Laser Entrance Hole Window Burst and Pressure Deflections at Cryogenic Temperature
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低温下激光入口孔窗破裂和压力变形
DOI：
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
S. Bhandarkar
中科院分区：
文献类型：
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作者：
B. Lairson;Ryan Smith;J. Guckian;T. Ayers;S. Bhandarkar
激光入口孔（LEH）窗必须具有最小的厚度，但必须在52千帕的可复制包膜中包含低温夯实气体。考虑到窗口故障的高成本，了解完成窗口的可变性是很重要的。在18k下测量了聚酰亚胺LEH窗口压力偏转曲线。利用薄膜弹性力学很好地描述了LEH窗口压力挠度的形状和大小。随后，从几个生产批次中选择24个3.9 mm孔径的窗户来测量再现性。将窗户冷却至18k，测量其泄漏率、挠度至52 kPa和破裂压力。18k时的平均窗口偏转为260 μm，标准差为20 μm。各向异性初始应变模型很好地描述了窗口挠度的变化。窗口破裂压力服从一阶威布尔统计量。使用条件下的预测故障率外推为<0.1%。
Abstract Laser entrance hole (LEH) windows for hohlraums must have minimal thickness yet must contain low-temperature tamping gas in a reproducible envelope at 52 kPa. Given the high cost of a window failure, it is important to understand variability in the finished windows. Polyimide LEH window pressure deflection profiles were measured at 18 K. The shape and magnitude of pressure deflections of LEH windows were well described using thin film elastic mechanics. Subsequently, 24 windows with 3.9-mm apertures were selected from several production lots to measure reproducibility. The windows were cooled to 18 K, and their leak rates, deflections to 52 kPa, and burst pressures were measured. The mean window deflection at 18 K was 260 μm, with a standard deviation of 20 μm. Variability in window deflections was well described by an anisotropic initial strain model. Window burst pressure was found to obey first-order Weibull statistics. The predicted failure rate for the use conditions was extrapolated to be <0.1%.