Generation of UHV with Turbomolecular Pump and Dry Backing Pump: Meeting the demand for completely hydrocarbon-free vacuum

摘要

For the generation of ultra-high vacuum (UHV), multiple pumps and pump combinations are possible. In the past, due to its high compression ratio, the most commonly used backing pump was the oil-sealed rotary vane pump. But the growing demand for hydrocarbon- free vacuum makes other solutions necessary: A completely magnetically levitated turbomolecular pump combined with a dry multistage Roots pump is not only able to generate oil-free UHV pressure but also eliminates contamination due to operating error. Residual gas analyses prove that with this pump combination, the limiting partial pressure of hydrogen can be significantly reduced.