Versatile Detector
Researcher to use grant to design versatile X-ray detector

Marianne Hromalik, a new computer science faculty member, completed her post-doctoral work at Cornell University this spring, but the “homework” has kept right on coming.

Marianne Hromalik.Cornell’s Laboratory for Atomic and Solid State Physics has subcontracted Hromalik to work on programming a versatile detector for X-rays used to examine the structure of viruses and proteins, to monitor materials fatigue in aircraft parts and to do much more.

Hromalik, who is part of Oswego’s three-member team for the planned electrical and computer engineering program, said she can see substantial benefits for Oswego from her partnership in the project.

“I can bring in a lot of students who are involved in the research,” she said. “I can take them to Cornell sometimes. Capstone candidates can do a piece of the work.”

The project also can mean new equipment and conference travel for SUNY Oswego, as well as peer-reviewed publication for Hromalik and her associates.

The personnel portion of Cornell’s three-year Department of Energy grant totals about $500,000, Hromalik said. SUNY Oswego will receive about 22 percent of that, or $34,974 a year for Hromalik’s one-day-a-week services to the larger project in Ithaca.

To begin to visualize Hromalik’s work, it may be handy for non-scientists to think of X-rays used in airports and hospitals. But the kind used in detailed molecular studies are called synchrotron radiation instruments, capable of imaging staggering numbers of X-rays to study substances and objects at nanoscale resolutions, in time intervals measured in billionths of a second.

Camera analogy

A sophisticated device called a pixel array detector—a multilayered integrated circuit driven by software—captures and stores the data generated in experiments using synchrotron X-rays. The rays help scientists observe the behavior of substances or objects subjected to cold, light, pressure and other stressors.

“It’s like a digital camera,” Hromalik said. “We’re using these (silicon) chips to drive the X-ray synchrotron. It’s like the controls of a camera.”

Machines to generate the X-rays are huge. “Often,” she said, “X-rays of the intensity used (in these experiments) are formed from linear accelerators—rings several kilometers long.”

In contrast, the detectors are small, about the size of the palm of a hand.

In the past, detectors have been designed for a specific experimental application. The development of detectors is years long and costly.

“What tends to happen here is the experimenters don’t wait on the detector to match what they want to do,” Hromalik said. “They just use whatever detector is available—which makes their research not as powerful or accurate as it could be.”

That’s where her expertise comes in. Hromalik, a native of the Caribbean nation of Trinidad and Tobago with a doctorate from the University of Sussex in England, is working on a field-programmable gate array implementation capable of changing the logic of a single detector to handle new jobs with only the download of new software.

“We can change its function by reprogramming different logic gates to make detection more flexible, without having to rebuild it every time we want a new application, which is what they do now,” Hromalik said.

The new assistant professor gave a presentation Sept. 21 at the Synchrotron Radiation Instrumentation Conference in Chicago.

Cornell researchers, Oswego computer science chair Douglas Lea and Hromalik are working with computer science major Benjamin Paretzky to calibrate for “noise” and other systematic errors caused by silicon defects in another detector developed in the larger grant.

Meanwhile, Hromalik is teaching courses in computer science—for example, an elective called digital signal processing—that eventually will form part of the requirements of the new electrical and computer engineering program, now in development.

Rachid Manseur, associate professor of computer science, leads the effort to create the new engineering program, with Adrian Ieta, assistant professor of physics, and Hromalik.

PHOTO CAPTION: Marianne Hromalik, assistant professor of computer science, displays a computer circuit board that includes a detector (bottom right gray rectangle) of the type use to capture and store X-ray data used in scientific research. Hromalik is working as a partner in a Cornell University grant to develop the software that will make detectors that are versatile and less costly.

(Posted: Nov 08, 2010)