Announcements

• Eckhard Elsen (DESY)

Pulsed RF Heating Effects in Normal Conducting L-Band Cavities

• V. Paramonov (Inst. for Nuclear Research, Moscow)

In present projects, such as the X-FEL and the ILC, the superconducting technology is chosen for the main linacs. However, in some special parts normal conducting cavities, operating with high electric and magnetic fields are applied. Under development are RF Gun cavities with an electric field at the cathode up to 60 MV/m. The capture section in the ILC positron source should operate at an accelerating gradient of 15 MV/m; similar cavities are required for the ILC electron source. The CDS booster cavity for the PITZ facility, which is presently under construction, is designed for an accelerating gradient of 14 MV/m, close to the required ILC parameters. The high filed strength leads to a high pulsed RF loss density. In combination with the long RF pulse (~ 1ms) it results in a significant surface temperature rise during the pulse and a corresponding cavity deformation and frequency shift. Results of 3D numerical simulations for temperature and displacements distributions and cavity parameter variations during the RF pulse are presented and compared with existing experimental data. Both, particularities and general properties of the RF pulsed heating effect in normal conducting L-band cavities are considered. The results lead to a better understanding of the cavity operation and system improvements.