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TY - CONF AU - Shibata, T. AU - Fan, K. AU - Hamano, K. AU - Ishii, K. AU - Matsumoto, H. AU - Sugimoto, T. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - The New Eddy Current type Septum Magnets for Upgrading of Fast Extraction in Main Ring of J-PARC J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - The J-PARC Main Ring (MR) is working on imporved beam to 750 kW by shorting the repetition period from 2.48 s to 1.3 s which we call 1Hz operation. The septum magnets for fast extraction in MR will be improved to the new septum magnets which can operate 1Hz. The new magnets will be installed to MR in 2021. In this poster we will report about the new low field septum magnet for the fast extraction. The present septum magnets are conventional type. Therefore, we have problem in durability of thin septum coil by its magnetic vibration, and large leakage field at the exit of the circulating beam duct. The new septum magnets are eddy current type. The eddy current type does not have septum coil, but has a thin septum plate. We can expect that there is no problem in durability of septum coil, and leakage field can be reduced. The output of the present power supply are pattern current which of flat top is 10 ms width, the new one is short pulse which of one is 10 us. The short pulse consists of fundamental and 3rd harmonic sin-wave pulse. We can expect that the flatness and reproducibility of flat top current can be improved. We confirmed that 1Hz operation and high accuracy of its output current and magnetic field with the new septum magnet system. We had some problem in unexpected instability of output current. In this report we also summarize the measure against the instabillity. PB - JACoW Publishing CP - Geneva, Switzerland SP - 1997 EP - 2000 KW - operation KW - septum KW - extraction KW - experiment KW - feedback DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-TUPTS029 UR - http://jacow.org/ipac2019/papers/tupts029.pdf ER -