Raman Snow Analysis

Last September, two undergraduate students were fortunate to be invited to a joint project between both Prof. Andrew Ault’s and Prof. Pratt’s research groups, through the University of Michigan Undergraduate Research Opportunity Program. The project intends to establish a protocol for imaging and analyzing snow crystals for climate research, specifically the impurity concentration and distribution in Arctic snow.

We intend to use the Raman spectrometer detailed in the previous December blog post “Raman Installation” for its imaging and elemental mapping capabilities. It is an exciting prospect to be among the first in utilizing Raman on snow crystals, however, we have run into several complications. The Ault group’s Raman spectrometer features a laser filter that can control its intensity. Higher settings generally result in increasing base resolution for imaging. Unfortunately, a high filter setting is a dual-edged sword as the laser will heat up samples. In our test run with the Raman, the laser burnt through the silicon sample several times! We will most likely use a low filter setting despite the base resolution drop.  

Linkam Stage (Placeholder for lab one)

A more immediate complication is the tendency for snow to melt, especially under the Raman’s laser. We’ve made progress in the last two months in finding a way to preserve the snow crystals long enough for Raman analysis. A Linkam cooling stage is in the Ault Lab which will allow us to keep samples at a stable -30°C during imaging. 

The Lab also has a recirculating cooler which will be paired with the Linkam stage once the necessary bath fluids are ordered. Soon after, we will be ready to begin determining parameters for imaging.

Placeholder for Freezer/Snow

The Ault Group has snow that is kept in the new freezers mentioned previously in the blog. It will be used along with natural Ann Arbor snowfall until we are ready to analyze our Arctic snow currently in storage. Hopefully we will continue updating our progress as we come closer to the Undergraduate Research Symposium in April!