The Effect of Technical Operational Parameter on the Performance Stability of RF-Power Transfer for Cyclotron DECY-13 in Yogyakarta

Abstract

Radio Frequency (RF) power transfer needs special condition in order to achieve high transmission coefficient, the matching condition between source and load must be met. In this case there are 3 important technical operation parameters, namely conductivity of cooling water, vacuum pressure, and magnetic field. They have influence on the impedance of the RF-generator load. An RF-generator of the frequency of 77.76 MHz having power up to 10 kW has been used in the construction of self-built cyclotron DECY-13 by BRIN in Yogyakarta. The experiment showed the increasing of power reflectivity up to 61% by rising of water conductivity 16%, i.e. 0.97 µS/cm, that used for cooling of the entire system inside the cyclotron chamber. The results also showed that the homogeneity of magnetic field from 1,5 to 2,0 ppm has changed the detected of impedance to be ~10 Ω at its real part and ~5 Ω at its imaginary part, by using network analyser based on Schmidt Chart analysis. On the other hand, the effect of vacuum pressure starting at 10−3 mbar to high vacuum have no significant effect on its real and imaginary parts of impedance.