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Electronic design of an Application-Specific Integrated Circuit (ASIC) developed by scientists at Washington University and SIUE. The collaboration has developed chips specifically for studying the properties of, and reactions between, atomic nuclei. (Image: Nuclear & Radiochemistry group)

A cross-disciplinary team of chemists and physicists from Washington University in St. Louis is building a better computer chip to improve detection and surveillance for the illegal transport of nuclear materials at U.S. borders. The work is part of a new, five-year, $10 million collaboration in low-energy nuclear science led by Texas A&M University. Under the new program, called CENTAUR, Robert J. Charity, research professor of chemistry, and Lee G. Sobotka, professor of chemistry and of physics, both in Arts & Sciences, are testing a novel neutron detection strategy and a related chip. The chip is being developed with long-time collaborator George Engel, a professor in the department of electrical and computer engineering at Southern Illinois University Edwardsville.

Roughly two dozen scientists across all partner universities will be involved in CENTAUR, along with their affiliated research groups. One of the center’s major contributions will be research and development expertise related to neutron detectors, which are relevant for both basic low-energy nuclear science and nuclear security applications.

“The problem with existing neutron detectors is that they are too big to get fine position information,” Sobotka said. “They needed to be big to get the required detection efficiency. The solution is to have many — tens of thousands — of small detectors. This had not been contemplated before as it requires a signal processing stream for each of the small detectors.”

ASICs — Application-Specific Integrated Circuits — form the backbone for data processing in computers, cell phones and other electronic devices. These custom chips are made because collecting oft-repeated tasks on one chip makes the overall task faster and less expensive to replicate.

Scientists don’t typically get involved with building their own ASICs, unless there is a highly specific need for the custom processing. For example, ASICs are developed for certain high-energy physics experiments, like those done at the European laboratory near Geneva — CERN — where the Higgs boson was discovered. ASICs are also used in some experiments in space and for medical physics devices like the Positron Emission Tomography (PET) device, which was developed by scientists from Washington University 40 years ago.

For their part, Sobotka, Charity and Jon Elson, a research engineer in chemistry, teamed up with Engel to build their own ASICs starting in 2001. The collaboration has recently upgraded two chips that they built and is making a third one honed for a different scientific task. CENTAUR researchers will use two of these chips in tandem, coupled with a particular organic crystal as their detector medium, to complete high-resolution experiments with neutrons that current detectors and signal processing electronics do not allow.

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