极高真空校准室内残余气体的成分分析  

Composition Analysis of Residual Gases in Extremely High Vacuum Calibration Chamber

作　　者：成永军[1] 李得天[1] 张涤新[1] 冯焱[1] 卢耀文[1] 赵澜[1] 徐婕[1] 

机构地区：[1]兰州物理研究所,真空低温技术与物理国家级重点实验室,兰州730000

出　　处：《真空科学与技术学报》2010年第1期54-59,共6页Chinese Journal of Vacuum Science and Technology

摘　　要：用四极质谱计对316L不锈钢制作的极高真空(XHV)校准室在烘烤前、后的残余气体成分进行了分析。一个热阴极电离规(IE514)和一个四极质谱计(QMS200)连接在XHV校准室上。烘烤前,开、关热阴极电离规以及对其进行除气,放出的气体主要有H2O、CO、H2、CH4和CO2。烘烤后,开、关热阴极电离规以及对其进行除气,放出的气体主要有CO、H2、CO2和CH4。整个烘烤过程完成后2h,XHV校准室内的压力在室温下通过分子泵串联抽气机组抽至8.97×10-9Pa,用四极质谱计分析到的残余气体成分主要为H2和CO。整个烘烤过程完成后4h,打开非蒸散型吸气剂泵(NEGP)对XHV校准室抽气,结果表明NEGP对H2具有较大的抽速,但对碳氢类化合物(如CH4)和惰性气体几乎没有抽速。用NEGP对XHV校准室连续抽气72h后,XHV校准室内的压力从8.34×10-9Pa下降到9.12×10-10Pa。不锈钢XHV校准室内的残余气体成分中大量的CO和CO2主要来自于四极质谱计。The compositions of the residual gases in the extremely high vacuum （XHV） calibration chamber, made of stainless steel with a volume of 316L,were analyzed with a quadrupole mass spectrometer （QMS） before and after baking at 300℃ to study the gas species evolution during degassing. Before baking and after the hot cathode ionization gauge was turned on and the degassing was done, the dominant outgas species were found to be H2O, CO, H2, CH4 and CO2. After baking,followed by on-and-off of the gauge and its degassing, the major out-gassed species were CO,H2,CO2,and CH4. The chamber was pumped down with a turbo-molecular pump to a base pressure of 8.97×10-9pa at room temperature, and the residual gases were H2 and CO two hours later. Interesting fmding is that the pumping speed of the non-evaperable getter pump （ NEGP ） is fairly large for H2, and little for hydrocarbons （CH4） and noble gases. After being pumped by the NEGP for 72 hours, the pressure in the XHV chamber dropped from 8.34×10- 9pa to 9.12× 10-210Pa. The residual gases, such as CO and CO2, possibly originated from the QMS.

关 键 词：不锈钢 极高真空 残余气体 四极质谱计 非蒸散型吸气剂泵 

分 类 号：TB77[一般工业技术—真空技术]