JACoW is a publisher in Geneva, Switzerland that publishes the proceedings of accelerator conferences held around the world by an international collaboration of editors.
TY - CONF AU - Tomizawa, M. AU - Arakaki, Y. AU - Kimura, T. AU - Murasugi, S. AU - Muto, R. AU - Nishiguchi, H. AU - Noguchi, K. AU - Okamura, K. AU - Shirakabe, Y. AU - Sugiyama, Y. AU - Tamura, F. AU - Yanaoka, E. AU - Yoshii, M. ED - Gianfelice, Eliana ED - Nagaitsev, Sergei ED - Kim, Dong Eon ED - Marx, Michaela ED - Schaa, Volker R. W. TI - Slow Extraction Operation at J-PARC Main Ring J2 - Proc. of HB2021, Batavia, IL, USA, 04-08 October 2021 CY - Batavia, IL, USA T2 - ICFA Advanced Beam Dynamics Workshop on High-Intensity and High-Brightness Hadron Beams T3 - 64 LA - english AB - A high-intensity proton beam accelerated in the J-PARC main ring (MR) is slowly extracted by using the third integer resonance and delivered to the experimental hall. A critical issue in slow extraction (SX) is a beam loss caused during the extraction. A dynamic bump scheme under an achromatic condition provides extremely high extraction efficiency. We have encountered a beam instability in the debunch formation process, which is estimated to be triggered by a longitudinal microstructure of the beam. To suppress this instability, the beam to the MR has been injected into the RF bucket with a phase offset. A newly developed RF manipulation, 2-step voltage debunch, has successfully pushed up the beam power up to 64.6 kW keeping a high extraction efficiency of 99.5\%. A drastic beam loss reduction has been demonstrated in the beam test using a diffuser installed upstream of the first electrostatic septum (ESS1). 8 GeV bunched slow extraction tests for the neutrino-less muon to electron conversion search experiment (COMET Phase-I) have been successfully conducted. PB - JACoW Publishing CP - Geneva, Switzerland SP - 219 EP - 224 KW - extraction KW - operation KW - timing KW - experiment KW - septum DA - 2024/03 PY - 2024 SN - 2673-5571 SN - 978-3-95450-225-7 DO - doi:10.18429/JACoW-HB2021-THDC1 UR - https://jacow.org/hb2021/papers/thdc1.pdf ER -