On a clear day in mid-December, in a small laboratory with a radiation warning on the door, three APS staff and five members of the Temple University Environmental Health and Radiation Safety Department clustered around two Marie Curie letters from the APS collections. We listened as Dr. Eyas Amr carried the radiation detector across the room, and the instrument’s slow clicking became a steady stutter. My own heartbeat sped in response. Were the letters actually radioactive?
Marie Curie—the first woman to win a Nobel Prize and the first person to win it twice—has become synonymous with radioactivity. In 1910, she successfully isolated radium, published A Treatise on Radioactivity, and established an international standard for radium emissions, a unit now known as the curie. She was also elected to the American Philosophical Society, and her acknowledgement letter of June 24 remains in the APS archives. The APS Miscellaneous Manuscripts Collection also contains her December 17 letter to Charles Jacques Bouchard, a French pathologist, requesting his support for her candidacy as a member of the French Academy of Sciences.
Gina Surita, Elias Larralde, and I took the letters to Temple after a hot tip from science writer Dava Sobel, whose latest book focuses on Marie Curie. At the November 2024 APS Member Meeting, Sobel described her delight at seeing the Society’s Curie letters in person (her talk begins at marker 3:13), but she also offered Adrianna Link, Curator of the History of Science Collections at the APS, a word of warning. Other institutions with Curie materials have found that her lab notebooks in particular are contaminated with radium-226, a radioactive isotope whose decay produces radon gas. Inhaling or ingesting radium-226 can result in anemia, leukemia, cataracts, or bone cancer, so the flaking notebooks presented a health risk to researchers who handled them. The APS letters appeared to be stable and intact, but had they been exposed to the same levels of radiation? Did we need to establish special housing and handling protocols to protect our staff and visitors? Adrianna was understandably concerned, and so was I!\
To assuage our concerns, I needed access to an instrument sensitive to the alpha radiation produced by radium-226, which is too low in energy to be reliably detected with a Geiger counter. Temple University Radiation Safety Officer Kurt Bodison and his team—including Susan Slatina, Beth Anne Zawacki, Thomas Eubig, and Dr. Amr—were thrilled with the opportunity to help. Their usual work involves testing and maintaining Temple University Hospital’s radiation sources, which include X-ray machines, computed tomography (CT) scanners, fluoroscopy units, and radiation therapy machines. Marie Curie’s letters, which provide a tangible link to the early history of the study of radioactivity, provided an exciting change of pace, and everyone had to take photographs.
As it turned out, the speeding crackle of the alpha- and beta- radiation detector was a false alarm. I had unwittingly placed the letters on top of a cabinet containing a radioactive germanium-68 source used to calibrate some of the hospital instrumentation. When we shifted the letters to the countertop across the room and scanned them again, the detector stayed blessedly silent. The Curie letters in the APS collections are not radioactive, and researchers can handle them safely. I still wouldn’t recommend licking your fingers to turn the page.