A Beam Bump with Programmable Width and Amplitude

A circuit producing a pulse of over 100 A and a width programmable from 2 to 16 ms has been developed to power a beam bump. The switching circuit involves two SCR´s. The pulse width is controlled by changing the timing of the SCR triggers. An inductance is in series with the circuit, and additional diodes have been used to avoid any overshoot or undershoot during switching. The beam bump is part of the damping system used for accumulation and storage of electrons and positrons in the Cambridge Electron Accelerator ring. During multicycle filling, the beam bump backleg windings move the beams approximately 1.5 inches transversly into the damping magnets while the beam energy is near maximum. In order to store the particles at constant energy, the ac component of the synchrotron magnets excitation is decreased and the dc component increased. At the same time, the beam bump pulse is continuously increased in width and finally switched into a steady-state condition. The conversion process is completed with no loss in beam current.