Design and development of high power window for linear accelerator at 2.856 GHz

This paper deals with design and development of high power RF window for S-band linear accelerator at spot frequency 2.856 GHz which is capable of handling peak and average powers of 6 MW and 25 kW, respectively, with VSWR and insertion loss 1.1 and 0.1 dB, respectively. The HFSS software is used for computation of diameter and thickness of ceramic and other required parameters. Further, analytical technique is used for calculation of inner diameter of water pipe for effective cooling. All parts of window are fabricated. The window is assembled and tested. The theoretical values of VSWR, insertion loss, and return loss are found in good agreement with corresponding experimental values. Further the effect of variation of thickness, dielectric constant of ceramic and frequency is also studied and it is found that VSWR, insertion loss and return loss are affected. The output parameters are computed with the help of HFSS software. The inner diameter of the adopter used for cooling is calculated with the help analytical technique and it is found to be 5 mm. The essential parts of the window are ceramic, ceramic holding circular waveguide, outer circular waveguide with water adopter, standard waveguide flange, and UHV conflate flange.