DARPA demos power-packed microscale vacuum pumps

Researchers have demonstrated a breakthrough technology for national security applications. Funded by the United States Department of Defence Advanced Research Projects Agency (DARPA), the team was able to showcase what it claims as the smallest vacuum pumps ideal for electronics and sensors that require a vacuum.

Examples of applications that can use this technology are highly sensitive gas analysers that can detect chemical or biological attack, extremely accurate laser-cooled chip-scale atomic clocks and microscale vacuum tubes.

In 2008, DARPA's Chip-Scale Vacuum Micro Pumps (CSVMP) programme set out to create a new class of ultra-high-performance vacuum micropumps. The programme achieved an ultimate goal of a vacuum pressure of 10^-6 Torr (1 Torr is 1/760 of 1 atmosphere) for a tiny 1mm³ compartment with the smallest, most power-efficient pumps ever created.

"The process of creating a vacuum in a room large enough to test a spacecraft, for example, is pretty straightforward," said Andrei Shkel, DARPA programme manager. "A sealed room, a large pump and ample power are all that is needed. That approach does not scale down to microscale vacuum chambers that are slightly larger than a grain of sand. We had to harness new kinds of physics to develop these pumps, requiring precision and miniaturisation techniques that have never previously been attempted. The results are now available for future applications in the smallest, most sensitive electronics and sensors."

The programme has reached a successful conclusion, and DARPA researchers at the University of Michigan; Honeywell International Inc.; and the Massachusetts Institute of Technology (MIT) demonstrated their pumps.

Researchers at the University of Michigan developed three different pumps in three different pressure categories. From lowest to highest pressure, the categories are microplasma Penning ion high vacuum, Knudsen mid vacuum, and high-frequency peristaltic rough vacuum pumps. Pictured below is a 24-stage microscale rough pump that uses tiny micromachined hexagonal compartments, where each element of the array is either a pump or a valve.