In the beginning of the 1960s the first experiment on the registration of TR generated by muons of cosmic rays was conducted on Mount Aragats. The research of TR became more powerful after the Yerevan Synchrotron started its work in 1967. Here, theoretical investigation of TR headed by Garibian was correlated with the experimental research headed by A. Alikhanian. Those studies played a decisive role in prompting similar work throughout the world: in the Brookhaven National Laboratory (by prof. Luke Chia-Liu Yuan), at Stanford Accelerator, and in different research centers of Europe.