LEYBONOL pump fluids for oil diffusion pumps must exhibit a low vapor pressure at room temperature and must be able to resist thermal decomposition and oxidization. They permit high pumping speeds over a wide range of pressures.

Surface tension of the pump fluids must be high to reduce “creep” of oil films. They are chemically inert, exhibit a high flash point and the evaporation heat is low. 
Mineral oils (LEYBONOL LVO 500 and LVO 510) for diffusion pumps are closely toleranced fractions of a high quality base product distilled with particular care.
These pump fluids are especially suited for work in a high vacuum.
Silicone oils (LEYBONOL LVO 520 and LVO 530) are composed of precisely defined chemical compounds and are highly resistant. Owing to their extremely low vapor pressure, silicone oils are particularly well suited as a working fluid. Even after numerous air inrushes, silicone oils suffer neither ageing nor mass spectrometrically apparent alterations. Strong mineral acids, alkalis and strong oxidants are capable of decomposing silicone oils.
LEYBONOL LVO 540 is a hydrocarbon compound and has been developed for utilisation in oil vapour jet pumps. It is thermally and chemically highly resistant and excels through a high degree of oxidation resistance. It delivers the essential high pumping speed of the vapour jet pumps in the medium vacuum range.