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TY - CONF AU - Yonehara, K. AU - Ankenbrandt, C.M. AU - Chung, M. AU - Derbenev, Y.S. AU - Freemire, B.T. AU - Johnson, R.P. AU - Kahn, S.A. AU - Sy, A.V. AU - Yoshikawa, C.Y. ED - Henderson, Stuart ED - Akers, Evelyn ED - Satogata, Todd ED - Schaa, Volker R.W. TI - Muon Beam Emittance Evolution in the Helical Ionization Cooling Channel for Bright Muon Sources J2 - Proc. of IPAC2015, Richmond, VA, USA, May 3-8, 2015 C1 - Richmond, VA, USA T2 - International Particle Accelerator Conference T3 - 6 LA - english AB - The six-dimensional ionization cooling is essential to design a bright muon source. A geometry constraint is a challenge issue in a compact helical cooling channel (HCC). Especially, the HCC requires a large bore helical magnet and a compact helical RF system to incorporate the RF into the magnet chamber. A new emittance evolution has been designed to mitigate the geometry constraint. The HCC was functionally separated into three parts sections. The lattice at the initial section provides a large transverse acceptance by using a strong helical focus magnet. Once the transverse beam size is small enough to get into the compact RF the HCC lattice in the middle section generates a large longitudinal beta tune to dominate the longitudinal cooling. Consequently, the longitudinal emittance becomes smaller than the transverse one at the end of middle section. In the final section, the magnetic field strength is gradually reduced to match out the helical channel to the straight solenoid. As a result, the emittance exchange takes place and the final transverse emittance becomes smaller than the longitudinal one. The new emittance evolution scenario will be discussed in this presentation. PB - JACoW CP - Geneva, Switzerland SP - 2203 EP - 2205 KW - plasma KW - emittance KW - collider KW - space-charge KW - simulation DA - 2015/06 PY - 2015 SN - 978-3-95450-168-7 DO - 10.18429/JACoW-IPAC2015-TUPTY074 UR - http://jacow.org/ipac2015/papers/tupty074.pdf ER -