For inner coating graphite baked in the atmosphere, gas desorption properties after exposure to the atmosphere were investigiated by using a thermal desorption spectroscopy. The temperature and the water vapor pressure during the exposure were varied from 25 to 50°C, and from 950 Pa to 6150 Pa, respectively. In the heating up to 410°C, the major gas species desorbed were CO
2 and H
2O. In the thermal desorption spectra of CO
2and H
2O, a desorption peak was observed at around 130°C. The peak intensities decreased with increases of both the exposure temperature and the water vapor pressure. When the water vapor pressure increased, the desorption amount of H
2O increased, although that of CO
2 decreased. The total desorption amount was almost the same even when the water vapor pressure was changed. In order to lengthen a life time of a cathode ray tube, it is necessary to reduce the water vapor pressure in the atmosphere environment, since the cathode is damaged by mainly the water.
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