Smithsonian Institute Develops Groundbreaking Microwave Spectrometer for Studying Interstellar Materials – EEJournal


Spectrum Instrumentation’s digitizer board is a key part of the vastly improved spectrometer

Großhansdorf, Germany – February 9, 2022. Microwave spectroscopy is a very powerful tool for discovering molecular structures and operates at very low temperatures close to absolute zero (1 to 5 Kelvin). The spectrometers generally operate with either high sensitivity over a very narrow bandwidth or a broad frequency with reduced sensitivity. Researchers at the Harvard Smithsonian Center for Astrophysics have used a Spectrum Instrumentation digitizer card to develop a next-generation, high-resolution, high-sensitivity molecular spectrometer capable of acquiring sample data much faster.

Brandon Carroll, a postdoctoral researcher on the project, explained: “The new sample chamber cooling design allows us to sample at a much higher rate than the usual design, over a wide bandwidth. We therefore needed a means to quickly collect large amounts of data over a wide bandwidth. Some colleagues at the University of California at Davis recommended a Spectrum Instrumentation digitizer card. We chose an M4i.2230 x8 card because of its massive amount of onboard memory, up to 1.5GHz bandwidth, and extremely fast averaging capability. We looked at cards from other companies, but they were more expensive or didn’t match our specs as well as the Spectrum card. Also, it was really easy to integrate with our software to fully automate the data collection process unlike the others we considered.”

Microwave spectroscopy is used to discern the shape and structure of molecules and this provides unique information about the changes that occur during chemical reactions. “Until we built this spectrometer, very complex instruments were required to study chemical reactions using microwave spectroscopy,” Brandon added. “Now we are able to study the detailed reaction dynamics of intermediate steps to see how it actually happens. The processes that dominate chemistry and physics change from those of higher temperatures when one is near absolute zero, which is the temperature in many parts of space, hence this Smithsonian Astrophysical Observatory research.”

This new spectrometer will provide insights into the chemistry of the interstellar medium, ie what is in the space between planets and stars. This material is the starting material for new solar systems and has a profound influence on the formation of planets – and even the origin of life.

He concluded: “The insights we gain from this new design will give us a much better understanding of interstellar chemistry, and we find that analyzing complex mixtures at ultracold temperatures is an exciting new direction for us.”

For two recent releases on the instrument see:


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