Abstract:

Igor presented the a parameter study to reach 800 MW in 0.7m PETS length required for the present HDS sturcture. Taking into account that a higher phase advance is favourable for the wakefields, he chose a structure with 140° per cell, 22.5 mm aperture that requires a beam current of 164A.
The HOM damping was simulated by GdfidL and HFSS, and Placet simulations show that there is practically no effect of the wakes seen.
The power extraction with an adiabatic matching section was optimized, the best result (better than -40dB for reflections and other modes) was obtained for 15 periods. A prototype of the 8 channel quasi-optical power extractor had been built and tested.
The ON/OFF capability is obtained by detuning using 4 wedges inserted in the damping slits. This mechanism could result in too high power to the loads which can be avoided by introducing a step in the slit.
Still the surface field can increase by ~20% during the wedge insertion. But Igor presented a design with a corrugated slotted wedge that even avoids this overvoltage, making a variable attenuator possible.
He showed some results of studies of imperfections and, finally, he briefly presented the ongoing activities and future studies.