Stability study of low energy buncher systems

Beam Bunching is the act of efficiently compressing a continuous (DC) beam of ions into a sequence of very narrow (<200ps) pulses, which is essential for injection into the acceptance phase space of the Superconducting heavy ion LINAC booster.  In order to achieve distortion-free acceleration, the bunching system must form pulses that are exceptionally narrow in time and in energy dispersion, namely the longitudinal phase space.  It is very essential to optimize the longitudinal phase space to achieve a very efficient transport through the booster.  These objectives has been achieved by use of a two-stage bunching system consisting of a room-temperature double-harmonic drift bunchers at the injection of the Pelletron accelerator and a superconducting cavity (super‑buncher) at the injection of the LINAC.  The first stage delivers typically 1-2ns beam bunches at the exit of the Tandem, which is further compressed to ~200ps by the super‑buncher.  This system has been has been working more than ten years.  However, there are inherent limitations due to the energy dispersion in the terminal stripper foils and the RF feedback electronics.  In this talk I will highlight these aspects and present results on the stability of low energy bunching system and measures to improve the phase space for better matching into the LINAC.