Absolut System provides cryopumping tailored solutions for large vacuum test chambers

In order to cope with growing demand on electrical propulsion, Absolut Systems develops specific test benches to characterize and optimize these electrical thrusters for a large range of thrust and thus for a large range of mass flow rate. These test benches are using cryogenic temperature and large surfaces to trap ionised flow emitted by the thruster and thus maintain the adequate high vacuum or ultra-high vacuum vacuum level (so called cryopumping process).

Absolut System has developed modelling and optimization tools of cryopumping system allowing optimal results for complex geometries.

This tool consists in the following steps:

  • A macroscopic analysis of the cryopump with empirical methods,
  • A thermal radiative analysis with finite elements (elaborated modelling of radiative exchanges) allowing the choice of the cryogenic coolers,
  • A Monte-Carlo molecular analysis allowing the validation of the pumping capacity of the specific geometry.

This iterative process requests an optimization between the low temperature cryopump (20-40 K) and the radiative screen systems (80-130K).

Left image under shows a vacuum chamber composed of a LN2 phase separator connected to LN2 tank used to cool down the 80K baffle and 40K panels of the cryopump inside the vacuum chamber actively cooled by single stage Gifford-McMahon cryocooler (AL230 style for Cryomech Inc.).