We have shown that it is possible to create a radioactivity characterized by the emission of positive or negative electrons in boron and magnesium by bombardment with alpha rays.

~ Irene Joliot-Curie

Irene Joliot-Curie Negative Possible Create

It was at the beginning of 1934 while working on the emission of these positive electrons that we noticed a fundamental difference between that transmutation and all the others so far produced; all the reactions of nuclear chemistry induced were instantaneous phenomena, explosions.

~ Irene Joliot-Curie

Irene Joliot-Curie Beginning Working