New associate professor researches cavities – University of Copenhagen

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24 June 2015

New associate professor researches cavities

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While cavities are a curse at the dentist's office, the majority of stones would be rather boring without their porosity. Enter Henning Osholm Sørensen, an expert in porous materials who has just been promoted to the position of associate professor in the Department of Chemistry's NanoGeoScience section. Sørensen’s goal is to shed light on porous stone.

The crucial role of cavities

North Sea chalk contains oil within its microscopic pores. And the size, shape and interconnectedness of these pores determine how much oil can be extracted. Likewise, porous mineral catalysts filter exhaust in the catalytic converters of diesel engines. Here, smaller and more numerous pores increase catalyst performance. In bones, the distribution of pores and minerals provides bone strength and elasticity. Therefore, chemists seeking to increase the recovery rate of oil, improve the catalytic effect of converters or develop artificial bones require a deeper understanding of porosity.

Three dimensional studies pivotal in repairing climate

Sørensen has served as an assistant professor at the Department of Chemistry for five years. Most recently, he has participated in NanoGeoScience research that explores the CO2 capture and storage potential of Danish chalk formations. The work requires extremely precise three-dimensional imagery of subsurface geological formations, including images of how pores change when exposed to the corrosive gas.

Intensely focused X-rays on hard materials

Sorensen uses what could be called a super x-ray microscope to get a better view of porous rocks, an instrument known as a synchronotron x-ray device. The device uses an extremely intense, highly focused x-ray beam to record 3D x-ray images of solid materials. But creating useful imagery requires more than being able to see through minerals.

Hair fine resolution

Pores in underground rocks are less than hair thin. Some of their channels can be as thin as 10 nanometres. That’s one ten-thousandth of the diameter of a human hair! So even x-rays strong enough to penetrate rock aren’t enough, as the resolution of these images must be capable of exposing the miniscule cavities being investigated.

New possibilities with large X-ray facility near Copenhagen

A handful of powerful enough x-ray spectroscopy facilities are scattered around the globe. For years, Sørensen and his colleagues have had to travel to the European Synchrotron Radiation Facility in Grenoble, France among other destinations, to obtain useful imagery. Now, a new – and in some ways better – facility is being built in Lund, Sweden, just an hour from Copenhagen. The MAX-IV facility will provide more time to perform measurements and thus, new possibilities for the study of porous energy-materials.

From raw data to fine photos

But even a keen eye isn’t enough to access the imagery produced by these advanced x-ray microscopes. Three-dimensional imagery generated by Henning Osholm Sørensen and his group requires between 5 and 10 minutes of shooting a beam through a gap no larger than the period at the end of this sentence. And, the initial output doesn’t even provide an image. The raw data must be processed first.

More bytes than 150 million books

A research group typically has a couple of days at a time to perform measurements, during which the instruments can collect more than 12 terabytes of data. This represents five times the amount of data found in the Royal Library’s collection of 30 million books. Transforming these initial terabytes of output into imagery relies on advanced data processing and decoding.

Sought after capabilities

A melange of deep chemistry insight, data processing experience and an understanding of advanced image processing make Sørensen sought after in circles beyond his own research group. Indeed, he claims that his greatest challenge is finding the time to participate in all of the many activities that pique his interest.

Henning Osholm Sørensen is married with Mette Sørensen. They have two children.