Describing her pioneering work on radioactivity in her biography of her husband and fellow researcher Pierre, Marie Curie wrote: To measure the very weak currents that could be passed through ionized air using uranium rays, I used an excellent device that had been studied and applied by Pierre and Jacques Curie.1
This same technique, now known as the Curie method, continued to be used in the Curie Laboratory until at least the 1950s. In the Curie Laboratory, it was the standard method for measuring radioactivity and the entire staff was trained to use it.
1Marie Curie, Pierre Curie, 1924.