Measurements of x-rays from the RF systems of the electron-linear accelerator for KEKB

RF systems of the electron linear accelerator are important sources of X-rays. In high power RF systems, X-rays become stronger and arc produced from many components. In KEK 8 GeV linear accelerator, the system consists of a klystron, a RF compressor, three RF dividers and a set of wave guides. The RF compressor called SLED, doubles the peak power of the microwave from the 50 MW peak power klystron. The energy of the microwave is divided into four by three RF dividers and goes to four accelerator tubes through the wave guide. X-rays from the klystrons and the SLEDs were measured by using TLDs and survey meters. Some SLEDs emitted X-rays more than others. X-ray spatial distribution around the RF system was measured by using the imaging plate (IP). Characteristic distribution was found around SLEDs based on the electric fields in the cavity. X-rays from the 1st divider were also found. It is well known that klystrons and SLEDs are the important source of X-rays. However, X-rays from other components were not well known. The measurements showed that X-rays were emitted from the center of the dividers and at the edges where they were welded. The electric field at the center is stronger than other part of the divider. A correlation between the electric field and the radiation field in the dividers were seen mostly. (author)