The material particle nature of primary cosmic radiation has been confirmed, although the processes turned out to be extraordinarily more complicated than we had assumed.

In this case, the particle formed has correspondingly less energy, whereas the product nucleus passes into the ground state with emission of the quantity of energy saved as gamma radiation.

Strict conservation of energy in the elementary process had thus been confirmed also by a negative experiment.

This result was confirmed by different researchers using various experimental arrangements.

Direction coupling between the various radiations generated in a nuclear reaction both with one another and with the initiating radiation can also be detected and measured by coincidences; this provides valuable information about the structure of the atomic nuclei.

Rossi was the first to describe another system working with valves in parallel; it has the advantage that it can easily be extended to coincidences between more than two events, and is therefore predominantly used today.