Margaret Melhase Fuchs and the radioactive isotope

Rebecca Trager tells the story of a brilliant female undergraduate who discovered caesium-137 in 1941 but was blocked from pursuing a PhD

The person who discovered the radioactive isotope caesium-137 – which is today one of the most widely used radionuclides in the world – was Margaret Melhase. What’s more, she did it as an undergraduate chemistry student at the University of California, Berkeley, in the US. Her remarkable finding in 1941 came about because Melhase managed to convince Glenn Seaborg, a rising star in nuclear chemistry, to set her up with a research project and lab space on the top floor of the university’s old chemistry building.

In the wake of Melhase’s discovery, Seaborg went on to share the 1951 Nobel prize in chemistry, serve as an advisor to at least nine US presidents, and an element was named in his honour in 1997. Melhase, on the other hand, disappeared into virtual obscurity. She graduated from UC Berkeley with an undergraduate degree in chemistry in 1941, and abruptly hit a roadblock when the chair of the university’s chemistry department – Gilbert Lewis – refused to let her pursue a graduate degree.