Recent development of a closed orbit monitor system in the KEK booster synchrotron

The KEK 500 MeV booster synchrotron is now under operating to provide a high intensity proton beam to a medium energy nuclear/neutron physics experiment, and also used as an injector into the 12 GeV main accelerator. The KEK accelerator complex is scheduled to serve an intense beam for a neutrino experiment and booster utility also foreseeing more intense protons to produce high intensity neutrons. The accelerator machine studies are going on in order to improve the current beam intensity as high as possible. A new close orbit distortion monitor system has been developed in the booster synchrotron to make more clear the beam orbit behavior during the acceleration period, during which the beam caused from some emittance blow up and preventing the intensity. The system consists of newly designed electrostatic beam position monitor (ESBPM), analogue to digital converter (ADC) and a graphic display. The detail of this system is described in this paper. (author) 10 figs