Abstract
In this investigation, the transpiration-mass spectrometer system, whose development was previously reported, has been improved and upgraded for better sensitivity and detectability by provision of molecular beam chopping device, new properly designed-skimmer orifice, shorter geometric arrangement between beam-origin and beam-detector and higher evacuation pumping system installation Particularly, the chopping system is being incorporated into this system, in order to differentiate the molecular beam of gaseous specimen molecules from residual gaseous molecules, thereby increasing the accuracy and improving the detectability. After these improvements, compared with the previous system, the sensitivity has been increased as much as 100 times and detection of about ten parts per million has been attained.
Using this improved system, vapor species and pressure of selected sulphides, GeS, SnS and CdS, have been measured by combining the conventional transpiration vapour pressure measurement method and the mass spectrometer for species identification. The resultant vapourization reactions and vapour pressures are as follows:
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oindentThese results are in good agreement with other research results.
