César Lattes and the techniques of production and detection of mesons: scientific practice as historical object

The main goal of this article is to present the scientific investigations of the Brazilian physicist César Lattes in the 1940s, which lead him to produce, capture and identify pi and mu mesons. Using unpublished primary sources hold by archives in Brazil and the United States, as the syllabus of the courses Lattes took and the notebooks from the Lawrence Radiation Laboratory, we analyze the experimental skills he had developed and improved. He has combined scientific instruments from different institutions using in his experiments theories that were recently appearing to reach his goals. Thus, we take Lattes’ scientific practice as a historical object, focusing on his strategies of detection which have conditioned his choices of the laboratories to develop his work.