Upgrade of J-PARC Fast Extraction System

The J-PARC main ring (MR) fast extraction (FX) system has two functions: to deliver a high power beam to the neutrino experimental facility and to dump the beam at any time in case of hardware failures. The present FX system consists of five bipolar kickers and eight bipolar septa. In order to raise the beam power to the design limit, both the beam intensity and the repetition rate will increase gradually. The FX system needs to be upgraded to satisfy the new requirements. The upgrade includes FX orbit optimization and new design of devices. Firstly, two high performance eddy current septa have been designed and fabricated. Then downstream high field septa are redesigned and using ceramic beam pipe to eliminate eddy current effects, which meets the requirement of high repetition rate operation. A new large physical aperture quadrupole is needed to accommodate high intensity beam. In order to evaluate the beam loss in the new system, realistic 3D beam tracking is studied.