The PITZ Booster Cavity--A Prototype for the ILC Positron Injector Cavities

A critical issue of the design of the Positron Pre-Accelerator (PPA) for the future International Linear Collider (ILC) is the operational reliability of the Normal Conducting (NC), high accelerating gradient L-band cavities. Now a Booster Cavity (BC), intended for increasing the beam energy at the Photo Injector Test Facility in Zeuthen (PITZ), and developed by a joined INR-DESY group, is under construction at DESY, Hamburg. With the PITZ requirements (accelerating gradient up to 14 MV/m, rf pulse length up to 900 mks, repetition rate up to 5 Hz) this cavity, which is based on the Cut Disk Structure (CDS), is a full scale, high rf power prototype of the cavities proposed for the PPA. The BC operation will allow us to confirm the main design ideas for the high gradient PPA cavities. A detailed technical study was performed during the BC design, resulting in some modifications for the PPA cavities, which are described in this paper. We also propose a program of rf experiments with the PITZ booster cavity for further improvements of the PPA structures.