RIT astrophysicists leverage cancer center to damage single-photon CMOS detectors for future space missions

A recent trip to a cancer center in Boston helped astrophysicists at the Rochester Institute of Technology reach a key milestone in their mission to develop advanced CMOS image sensors for future NASA space missions. Researchers at RIT’s Center for Detectors irradiated single-photon detection and photon-count resolution CMOS detectors with protons at the Francis H. Burr Proton Therapy Center at Massachusetts General Hospital.

The researchers, led by Don Figer, principal investigator of the grant and director of the Future Photon Initiative at RIT and the Center for Detectors, are testing detectors that could one day identify individual photons from faint sources such as distant, habitable planets. . At RIT, they are able to simulate a space environment by using cryogenic chambers to create a vacuum and cool the device to the cryogenic temperatures it would experience in space. However, outer space is full of radiation that damages electronics, so researchers need to know how this radiation degrades detector performance.

“When you have a telescope in space with a detector, there’s a certain amount of radiation incident on it,” said a PhD in science and technology in astrophysics. student Lazar Buntic. “Although there are many types of radiation, most of it comes from the sun, which ejects a lot of protons and when they hit the detector they cause problems. The way we simulate this on Earth is that we enter a radiation test facility that has a way of creating that radiation and exposing our detector to it.

Buntic has called the MGH facility one of the best facilities in the world for controlling proton energy. While the facility is busy treating cancer patients throughout the week, the RIT team was able to use it over the weekend when the facility allows third parties to rent the proton beam line. The team loaded their sophisticated gear into a moving truck the Friday before Halloween, made the trip to Boston, and completed their tests in a dizzying 36 hours.

More than a year before irradiating the detectors, RIT researchers were able to simulate the dose of solar protons the detector would receive for an 11-year mission to the same location as the James Webb Space Telescope. The researchers chose to bombard the device with ten times the simulated dose, stopping at various large doses, to understand how the detector’s performance would scale and degrade beyond the expected mission lifetime.

“When you’re spending billions of dollars on these future space missions, you need to make sure the technology is up and running,” said Justin Gallagher, lab engineer for the Center for Detectors. “One of these tests is to measure and see the degradation. We need to quantify the decrease in performance of our device in a ‘simulated in space’ environment.

Gallagher and Buntic, who carried out the tests at MGH, said they were encouraged by the early results and the detector appears to exceed expectations.

For more information about the Center for Detectors, visit the Center for Detectors website.

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