Operating characteristics and beam breakup measurements in the superconducting recyclotron

The Stanford 500 MeV superconducting electron recyclotron designed for eight accelerator sections each 5.65 meters in length and four orbits of recirculation ( 5 passes through the linac) is described. Assuming an energy gradient of 2.2MeV/m and an injection energy of 7.0MeV, the machine is capable of achieving 500MeV. At present with three accelerator sections an energy of 115-120MeV has been achieved and the stability of recirculated electrons beam is found to be excellent. Experimental study on regenerative beam breaking in the recyclotron was carried out. Relative values of the power coupled from the beam to the breakup mode for both one pass and two pass operation are presented. The coupled power is positive for -18O deg < Δ PHI1 < 0 and is negative for 0<Δ PHI1 <180 deg, independent of the sign of the coupled power for one pass operation ( Δ PHI1 - is the phase shift of the returning beam). The given measurements showed qualitative agreement with the simple model calculations