We have measured the water and hydrogen outgassing rates of seven vacuum chambers of identical geometry but constructed of different materials and heat treatments. Chambers of five different materials were tested: 304L, 316L, and 316LN stainless steels; titanium (ASTM grade 2); and 6061 aluminum. In addition, chambers constructed of 316L and 316LN stainless steel were subjected to a vacuum-fire process, where they were heated to approximately 950 °C for 24 h while under vacuum. These latter two chambers are designated as 316L-XHV and 316LN-XHV. Because all the chambers were of identical geometry and made by the same manufacturer, a relative comparison of the outgassing rates among these chambers can be made. Water outgassing rates were measured as a function of time using the throughput technique. The water outgassing results for 316L, 316LN, 316L-XHV, and 316LN-XHV were all similar but lower than those for 304L by a factor of 3–5 lower at 10⁴ s. The water outgassing results for the Ti and Al chambers were closer to that of 304L, Ti being slightly lower. Hydrogen outgassing rates were measured using the rate-of-rise method and performed after a low-temperature bake of 125–150 °C for a minimum of 72 h. The Ti, Al, 316L-XHV, and 316LN-XHV chambers all have ultralow specific outgassing rates below 1 × 10⁻¹¹ Pa l s⁻¹ cm⁻² and are a factor of 100 or better than the 304L chamber. The 304L, 316L, and 316LN chambers with no vacuum-fire heat treatment have larger hydrogen outgassing rates than the other chambers, with determined specific outgassing rates ranging between 4.0 and 8.0 × 10⁻¹¹ Pa l s⁻¹ cm⁻². We conclude that Ti, Al, 316L-XHV, and 316LN-XHV have hydrogen outgassing rates that make them excellent choices for ultrahigh vacuum and extreme-high vacuum applications, the choice depending on cost and other material properties.

中文翻译：

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七个不同材料和热处理的几何相似的真空室的脱气率比较

我们测量了七个几何形状相同但由不同材料和热处理构成的真空室的水和氢气脱气率。测试了五种不同材料的腔室：304L，316L和316LN不锈钢；钛（ASTM 2级）; 和6061铝。此外，对由316L和316LN不锈钢制成的腔室进行真空燃烧，在真空下将其加热到大约950°C保持24小时。后两个腔室分别命名为316L-XHV和316LN-XHV。因为所有腔室的几何形状相同，并且由同一制造商制造，所以可以对这些腔室中的除气速率进行相对比较。使用通过量技术将水的除气速率作为时间的函数进行测量。316L，316LN，⁴ 秒 Ti和Al腔室的放气结果更接近304L，而Ti则稍低。使用上升速率法测量氢气的脱气速率，并在125-150°C的低温烘烤至少72小时后进行。Ti，Al，316L-XHV和316LN-XHV腔室均具有低于1×10 ^-11  Pa l s ^-1  cm ^-2的超低比排气率，并且比304L腔室高100倍或更好。未进行真空喷火热处理的304L，316L和316LN腔室的氢气除气率比其他腔室大，确定的特定除气率在4.0和8.0×10 ^-11  Pa l s ^-1  cm ^-2之间。我们得出的结论是，Ti，Al，316L-XHV和316LN-XHV具有氢气放气速率，这使其成为超高真空和超高真空应用的极佳选择，具体取决于成本和其他材料性能。