Bruno Rossi was an Italian experimental physicist. He made major contributions to particle physics and the study of cosmic rays.
A 1927 graduate of the University of Bologna, he became interested in cosmic rays. To study them, he invented an improved electronic coincidence circuit, and travelled to Eritrea to conduct experiments that showed that cosmic ray intensity from the West was significantly larger than that from the East.
Forced to emigrate in October 1938 due to the Italian Racial Laws, Rossi moved to Denmark. Where he worked with Niels Bohr.