MEASUREMENT OF AVERAGE MOMENTUM AND COMPOSITION OF SECONDARY BEAMS OF PARTICLES FROM ACCELERATORS.

A time-of-flight method for measuring the average momentum, the momentum spread, and the composition of secondary particle beams, based on studying the time structure of the beam from the synchrocyclotron is described. The difference in the times of flight of particles having different masses (e** plus , pi ** plus , p, D, T, **3He) over a distance L from the target to the exit from the magnetic channels is measured. Amplitude discrimination of the signals from a counter is used to increase the accuracy of the time-of-flight measurements, while the time scale of the time-of-flight spectrum is calibrated according to the time structure of the accelerator beam whose period T//r//f is known with high accuracy.