Their electrodynamic ion funnel is a series of conductive, progressively smaller electric ring electrodes that efficiently pull in and focus more ions into the mass spectrometer than without the funnel. This makes mass spectrometers tremendously more sensitive. Fortunately, the ion funnel works best when its surrounding environment has an air pressure of about 5 torr, which also happens to be the atmospheric pressure on Mars.
"We didn't specifically design the ion funnel for space exploration, but we're excited that it and Mars are a good fit," said Tang.
JPL asked PNNL to help test whether the combination of laser ablation and an ion funnel could make in situ, or "in place," mass spectrometry possible on Mars. A standard laboratory mass spectrometer was equipped with laser and an ion funnel attachments, and the ion funnel end was placed inside a sealed chamber that matched Mars' atmospheric conditions. The researchers shot laser pulses at various samples, such as copper, stainless steel and gypsum. As they suspected, a small layer of each sample's surface atoms was transformed into ions and the ion funnel quickly pulled them into the mass spectrometer, which identified the samples.
"This system could be developed into a 'point and shoot' instrument for space analysis," Johnson said.
The results are promising, but further work is needed to develop ion funnel-equipped mass spectrometers ready for space. The next step is to make the system as small and light as possible so it could be used on a space exploration rover. The authors plan to pare it down enough to fit onto a rover's robotic arm.
|Contact: Franny White|
DOE/Pacific Northwest National Laboratory