VECC, Kolkata, India
The K500 Superconducting Cyclotron (SCC) has been developed indigenously and commissioned at VECC. The three-phase Radio-Frequency (RF) system of SCC, consists of three half-wave cavities placed vertically 120 deg. apart. Each half-wave cavity has two quarter-wave cylindrical cavities tied together at the centre and symmetrically placed about median plane of the cyclotron. Each quarter-wave cavity is made up of a short circuited non-uniform coaxial transmission line (called "dee-stem") terminated by accelerating electrode (called "Dee"). The SCC, operating in the range 9 to 27 MHz, has amplitude and phase stability within 100 ppm and 0.1 deg. respectively. The overview of all the subsystems of the cyclotron along with low-level RF (LLRF), high and low power RF amplifiers, cavity analysis, absolute Dee voltage measurement using X-ray method, amplitude and phase control loops will be presented in the talk. The commissioning of the cyclotron with first harmonic Nitrogen4+ beam extracted at 252 MeV, while operating at 14 MHz RF frequency, along with the correction of first harmonic magnetic field error by repositioning the cryostat within 120 micron accuracy, will be discussed briefly.
IBS, Daejeon, Republic of Korea
Rare Isotope Science Project (RISP) in the Institute of Basic Science (IBS), Daejeon, South Korea, is developing the high-energy superconducting(SC) linac composed with two types of superconducting cavity, single spoke resonator type-1 (SSR1) and type-2 (SSR2). Both cavities have same frequency 325MHz, but different beta, 0.3 and 0.51 each. For operating SC cavity within the target frequency, all outer disturbances should be removed or avoided. As a view of mechanical vibration, comparably low frequency up to 20kHz always happens as a consequence of combination between outer disturbance and resonant frequency of SC cavity. In this paper, we will show the design layout of SSR2 and its specifications. And also the mechanical resonance analysis for both bare and dressed cavity will be analyzed with numerical analysis program.