Enhancement of the rf characteristics of a soda dummy load by reduction of the skin depth effect

A new soda water dummy load is developed by considering the skin depth effect. Compared with the conventional soda dummy load where the resistive medium is filled both in the inner and outer cylinder, the soda water only exists on the annular volume so as to reduce the skin depth effect at the new design. The length of the soda water column is 97 cm and the input port size of the rf power is 9(3/16) in. The maximum allowable rf power is about 1 MW at the flow rate of 50 m3/h. ition, the mechanical effort is also added for sealing the soda water at the top region of dummy load due to the water pressure imbalance on the sealing region. The water pressure distribution of the top region for the conventional and new one are calculated by the commercial software for the fluid dynamics named CFX and a bar type supporter made by a high purity alumina (96%) fix the water leak problem. The cold rf-test using the network analyzer shows that the VSWR is less than 1.15 up to 200 MHz for the new one whereas the VSWR for the conventional one is as high as 1.3 around 200 MHz. The VSWR is less than 1.35 for the temperature variations of the soda water from 35 °C to 45 °C.