|Example of a Wilson chamber photograph|
Her earliest work with Frédéric Joliot-Curie and also his assistant Berthelot
was to measure the alpha decays of heavy ions by using the low pressure Wilson chamber of
F. Joliot-Curie (it could lower the pressure to 1 cm Hg, which allows to enlarge the tracks up to 76 times).
Next, she worked on the beta decay spectrum of artificial radioactive nucleus produced from the cyclotron
(the first one in Europe). She was awarded her PhD for this work. After the war, she worked on beta decay
in order to descriminate between models of the weak-interaction.
At that time, there were two types of transitions studied: the Fermi and the Gamow-Teller ones.
She was a very enthusiastic researcher. Even when she was displaced to Berlin in 1944
(Berlin was under the worst fire), she visited Berlin University and worked to build a spectrometer.
This spectrometer was hidden in her back-sack when she was sent back to Japan by the Soviet Union troops.