The injector is a linear accelerator which is composed of 56 disk loaded wave guide accelerating sections of 3.05 meters long each and some focusing cells with a total length of 202 meters and can accelerate electrons and positrons to 1.1-1.4 GeV. The emission current of the nanosecond electron gun is 5 amperes. The beam intensity of electrons from the injector is 600 milliamperes while that of positrons is 9 milliamperes.