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.

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.

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

To demonstrate this simultaneity is by no means trivial, because it may for example happen that the product nucleus always forms in an activated state at first.

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.

Many applications of the coincidence method will therefore be found in the large field of nuclear physics, and we can say without exaggeration that the method is one of the essential tools of the modern nuclear physicist.

The Laboratory for Radioactivity consisted of only two rooms at the time; at a later date, when tests of radioactive substances became more extensive, it expanded into four rooms.