Development of high current injector for the Osaka University Picosecond Single Bunch Electron Linear Accelerator

The subharmonic prebuncher system of the Osaka University Single Bunch Electron Linear Accelerator has been improved in order to increase a single bunch charge form 14 nC to 60 nC. Such most appropriate bunching condition for a large current beam injection into acceptance angle of a prebuncher was calculated by a one-dimensional disk model. The previous 6 th subharmonic prebuncher (SHPB) was replaced with two 12 th SHPBs and 6 th SHPB that are newly constructed. In January, 1984 the single bunch beam succeeded in an acceleration up to 67 nC over a goal. The bunch compressor was installed in the transport system to compress width of the large current single bunch and bunch width was shortened from 20 ps to 9 ps. In order to get the charge of 100 nC, an improvement of the prebuncher rf system, also development of an avalanche pulser and a new type electron gun are planned. (author)