MASS-SPECTROMETRIC EVALUATION OF THE DESORPTION PROPERTIES OF SOME GLASSES UNDER HIGH APPLIED VOLTAGE CONDITIONS

The manufacture of vacuum devices such as lamps, electronic tubes and displays requires a careful evaluation of the desorption properties of glasses under specific operating conditions. An exceedingly high gas load can detrimentally affect the vacuum and reduce the overall device performances. In the present study, the effects of the application un der vacuum of high voltages (3-9 kV) on a CRT and two soda lime glasse s were investigated, as a function of the glass temperature (60-100 de grees C). Outgassed species were collected by a quadrupole mass spectr ometer which was mounted with the ion source close to and in direct vi ew of the sample, to minimize the reactive gas species loss due to sur face interactions and recombination. The release of oxygen and oxygena ted gases from soda lime glasses upon high voltage application was mea sured, providing some evidence that electrolytically induced ionic tra nsport phenomena take place through the glass network under these cond itions. A comparatively lower outgassing rate from the CRT glass was m easured.