Henri Becquerel

About me:

I am a French scientist, born 1852 in Paris. I accidentally discovered spontaneous emission of radiation while he was studying phosphorescence in 1896. X-rays had recently been discovered, so I was trying to find a link between them and phosphorescence. I wrapped photographic plates, which would darken when exposed to light, in black paper. When I placed potassium uranyl sulfate (K2UO2(SO4)2), on top of the covered plates, the plates were darkened. I reasoned that it could not be light because the black paper would have absorbed it, so a new type of ray that could pass through paper must be the cause.

I found that only salts containing uranium would darken the plates, and pure uranium metal would produce a ray that was four times as intense, calling them Becquerel rays. Later, Peter and Marie Curie discovered that polonium and radium also emitted these rays, calling them radiation.

Experiments in the twentieth century found alpha particles (α, 42He), beta particles (β, electrons and positrons), and gamma rays (γ). For my work, I shared the 1903 Nobel Prize in Physics with the Curies. The SI unit becquerel (Bq, one nucleus decay per second, equal to s-1, similar to the hertz) was named after me in my honor.