Imaging nuclear fallout with a camera and a scintillating crystal

Our guest this week, Dr. Ari Foley, is a recent (July 2021) OSU graduate from the School of Nuclear Science and Engineering. For her PhD research, she developed a rapid imaging method for post-detonation nuclear forensics. While methods to do this work already exist, a lot of them are time- and material-intensive. Therefore, the goal of Ari’s work was to develop a method that could inform optimized destructive analysis of samples after a detonation event of a nuclear weapon, with a particular focus on reducing the amount of imaging time required. Not only was Ari able to accomplish this task but the system she developed is able to take an image of the spatial distribution of radiation omitted from an object in the same exposure as taking a traditional photograph of the object being analyzed (see Image below). How in the world did Ari do this? Read below for a short synopsis or even better listen to the episode here!

A core component of Ari’s system was an electron-magnifying charged couple device, also known as an EMCCD. The CCD part of that is essentially a normal camera but the EM part magnifies the signal collected from whatever the camera is pointed at. Ari rigged an inorganic scintillation crystal to the EMCCD, which sits in a 3D-printed holder just in front of the camera. The purpose of the crystal is that once it is held in close proximity to radioactive fallout material from a detonation, the radiation interacts with the crystal, which leads to the emission of light. This light is proportional to the amount of energy that is imparted within the crystal. The EM part of the EMCCD kicks in as the image is taken as it allows for a high intensity image to be made that magnifies the light emitted from the crystal interacting with the radiation. This process needs to occur in light tight box, however it is mobile, meaning that it can easily be taken into the field and directly be used at a nuclear detonation site to measure the intensity of radiation of fallout material.

Ari spent the last three years of her PhD time in Idaho at the Idaho National Laboratory (INL), which is one of the leading nuclear research labs in the USA and has close ties with OSU. In fact, Ari was one of two students in the inaugural class of INL Graduate Fellows, which enabled her to conduct this work while working full-time at the lab. However, Ari’s career may have gone down a very different path because she had always wanted to be an Arts student or pursue a career in human rights. However, during a summer school experience during her high school years, Ari attended a class on Indigenous Peoples and the United Nations. During this class, the students took a trip to the United Nations General Assembly Building in New York, which hosts a statue from Hiroshima, Nagasaki. The statue is of a woman holding a lamb, which from the front, looks completely normal. However, when you walk around to the back of the statue, the statue is completed charred and scarred – a consequence of the atomic bomb. The same class presented case studies of radiation contamination on tribal reservations in the USA. Seeing and learning these things really riled Ari up at the time because while she had been interested by radiation in chemistry class, she was suddenly confronted by the fact that radiation contamination were actual ongoing world issues. 

Listen to the podcast episode here to learn more about the nitty-gritty of how Ari developed her nuclear forensic system, how she prevented from getting radiation in the lab, and her road to OSU!

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