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yftnb
第11楼2008/03/20
书上答案：
Ions formed in the source of the mass spectrometer must reach the detector for them to be of any value. the average distance that an ion travels between collisions - the mean free path - at atmospheric pressure is around 10-8 m, and it is therefore unlikely that it will reach the detector under these conditions. since the mean free path is inversely proportional to the pressure, reducing this to 10-6 torr will increase the mean free path to around 10 m, and thus allow ions to reach the detector of the mass spectrometer.
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tuqw
第17楼2008/04/12
问一下，如果是离子井的，离子井里的真空度应该达到多少？如果我要往下做三级四级，如果浓度很大，离子化效率也可以是不是也有可能是我的真空度不太好？
yftnb 发表:书上答案：
Ions formed in the source of the mass spectrometer must reach the detector for them to be of any value. the average distance that an ion travels between collisions - the mean free path - at atmospheric pressure is around 10-8 m, and it is therefore unlikely that it will reach the detector under these conditions. since the mean free path is inversely proportional to the pressure, reducing this to 10-6 torr will increase the mean free path to around 10 m, and thus allow ions to reach the detector of the mass spectrometer.
