GETTERING OF RESIDUAL GASES AND THE ADSORPTION RATE OF HYDROGEN ON EVAPORATED MOLYBDENUM FILMS AT LIQUID NITROGEN TEMPERATURES
Mass spectrometric results indicated that an evaporated molybdenum film deposited on a water-cooled substrate in an ultrahigh vacuum system is a broad spectrum getter. The partial pressures of all residual gas components with mass- to-charge ratios of less than 45 were reduced with the exception of the inert gases. Evaporating molybdenum on a substrate at liquid nitrogen temperature further reduced the total residual pressure in the vacuum system and specifically reduced the partial pressure of argon to below the mass spectrometer sensitivity limit of 1 x 10/sup -9/ mm Hg. The maximum hydrogen pumping speed or sticking probability on molybdenum films at liquid nitrogen temperature was more than twice that at room temperature. It was also found that the rate of hydrogen adsorption or hydrogen sticking probability on liquid-nitrogen-cooled molybdenum films is not a monotonically decreasing function of the quantity of hydrogen adsorbed. (auth)
- Research Organization:
- California. Univ., Livermore. Lawrence Radiation Lab.
- DOE Contract Number:
- W-7405-ENG-48
- NSA Number:
- NSA-16-010546
- OSTI ID:
- 4809986
- Report Number(s):
- UCRL-6652
- Country of Publication:
- United States
- Language:
- English
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