A clean and large throughput differential pumping system developed by Institute of Modern Physics(IMP), CAS passed the technical evaluation in Lanzhou on 28th October 2010.

The highlight of the design is in the intermediate flow range (102Pa~10-1Pa) a new kind of molecular-drag pump with a small volume and oil-free developed by the research group is used in the system to replace the Roots pump unit which has a large volume and has a big problem of back-streaming of its backing pump oil.

Based on the considerations in the technical design mentioned above, a clean and large throughput differential pumping system (Fig.1) with a small volume and very low energy consumption was tested and built up successfully at IMP.

This is the first time to adopt the design in a differential pumping system around the world.

The differential pumping system has been applied for the Gas-filled Recoil Separator built in one of the terminals of Heavy Ion Research Facility in Lanzhou (HIRFL).