BBU Instability of ``Dragon-I'' LIA
- Received Date: 2008-01-11
- Accepted Date: 1900-01-01
- Available Online: 2008-01-04
Abstract:
BBU (Beam breakup) instability once appeared in the early stage of ``Dragon-I'' LIA, which was excited by TM110 mode stimulated when the eccentric beam passed through the multi-functional cavity(MFC). The radio frequency characteristics of MFC were analyzed with three methods such as analytic calculation, numerical computation, and measurement. The frequency of the TM110 mode from these methods agreed with the experimental results, while the transverse coupling impedance was different from the experimental results by some times. The main BBU exciter was the big transverse coupling impedance of the MFC which could be concluded. A grid was designed to shield the gap of the MFC. The experiments show that the BBU was compressed and the high frequency oscillation disappeared.