• A. Kiyomichi, T. Adachi, S. Murasugi, R. Muto, H. Nakagawa, J.-I. Odagiri, K. Okamura, H. Sato, Y. Sato, S. Sawada, Y. Shirakabe, H. Someya, K.H. Tanaka, M. Tomizawa, A. Toyoda, E. Yanaoka
  KEK, Ibaraki
• T.I. Ichikawa, K. Mochiki, S. Onuma
  Tokyo City University, Tokyo
• K. Noda
  NIRS, Chiba-shi

J-PARC (Japan Proton Accelerator Research Complex) is a new accelerator facility to produce MW-class high power proton beams at both 3GeV and 50GeV. The Main Ring (MR) of J-PARC can extract beams to the neutrino beam line and the slow extraction beam line for Hadron Experimental Facility. The slow extraction beam is used in various nuclear and particle physics experiments. A flat structure and low ripple noise are required for the spills of the slow extraction. We are developing the spill control system for the slow extraction beam. The spill control system consists of the extraction quadrupole magnets and feedback device. The extraction magnets consist of two kinds of quadrupole magnets, EQ (Extraction Q-magnet) which make flat beam and RQ (Ripple Q-magnet) which reject the high frequent ripple noise. The feedback system, which is using Digital Signal Processor (DSP), makes a ramping pattern for EQ and RQ from spill beam monitor. Here we report the construction status of the extraction magnets and the development of the feedback system.