At age 23, she was the youngest and only female member of the team which built and experimented with the world's first nuclear reactor (then called a pile), Chicago Pile-1, in a project led by her mentor Enrico Fermi.

She worked with Fermi on the Manhattan Project, and she subsequently helped evaluate the cross section of xenon, which had poisoned the first Hanford production reactor when it began operation.

She later worked at the Institute for Advanced Study in Princeton, New Jersey, the Brookhaven National Laboratory, and New York University, where she became a professor in 1962.

In later life she became interested in ecological and environmental issues, and she devised a method of using the isotope ratios in tree rings to study climate change.

[1] She graduated from Lyons Township High School in La Grange at 14, and received her BS in chemistry from the University of Chicago in 1938, at the age of 18.

[1][2] After passing her qualifying exams in chemistry, she approached the Nobel Prize for Physics laureate James Franck about being his graduate student, having been impressed by a talk he gave in 1939 on Brillouin zones.

"[4] Despite the fact that Franck did not look malnourished, she took the warning seriously, and decided to instead become a graduate student of Robert Mulliken, who would one day become a Nobel laureate himself.

[4] Her doctoral thesis, "On the Silicon Oxide Bands",[5] prepared under the supervision of Mulliken and Polish chemist Stanisław Mrozowski was accepted in 1943.

Anderson discovered that Woods was adept with vacuum technology from her research, and as soon as her PhD was finished, he hired her to work with the boron trifluoride detectors used to measure neutron flux.

[6] Fermi's group constructed a nuclear reactor known as Chicago Pile-1 under the stands of Stagg Field, the University's abandoned football stadium, where Woods had once played squash.

Walter Zinn did not want a woman involved in the dirty work of placing the graphite blocks, but Woods had plenty of work to do with the detectors and thermocouples, and used a small stack of graphite of her own to measure the effects of a radium-beryllium source on manganese foil to obtain a measure of the neutron cross section in order to calibrate the detectors.

"[9] Laura Fermi remembered Woods as "a tall young girl built like an athlete, who could do a man's job and do it well.

After a morning with Willard Libby soldering a canister containing a mixture of radium salt and beryllium metal, Woods absorbed about 200 roentgens, and her white blood cell count halved.

The doctors gave her a lecture on how a woman has only a fixed number of egg cells, a proposition that Woods was skeptical of.

After working through the numbers with slide rules and hand calculators, they determined the neutron cross section of the poison, which turned out to be xenon-135.

[15] Asked many years later about how she felt about her involvement in the Manhattan Project, she said: I think everyone was terrified that we were wrong (in our way of developing the bomb) and the Germans were ahead of us.

"[17] After the war, Leona Marshall returned to the University of Chicago, where she became a fellow at Fermi's Institute for Nuclear Studies.

John Marshall returned to the Los Alamos Laboratory, while Leona, now effectively a single mother,[1] became a fellow at the Institute for Advanced Study in Princeton, New Jersey in 1957.

[18] The following year she became a fellow at the Brookhaven National Laboratory, at a time when the focus of research in physics was shifting away from the nucleus and towards elementary particles.

[1][18] Now known as Leona Marshall Libby, she became interested in ecological and environmental issues, and she devised a method of using the isotope ratios of oxygen-18 to oxygen-16, carbon-13 to carbon-12, and deuterium to hydrogen in tree rings to study changes in temperature and rainfall patterns hundreds of years before records were kept, opening the door to the study of climate change.