Update on RFFAG ring for ν STORM JB. Lagrange, J. Pasternak Imperial College
Outline Enge fringe field fall-offs Change in the lattice Design of the straight magnets Collaboration JB Lagrange - phone meeting - 07/02/14 2
Outline Enge fringe field fall-offs Change in the lattice Design of the straight magnets Collaboration JB Lagrange - phone meeting - 07/02/14 3
Enge fringe field fall-offs To validate the dynamical aperture, more realistic fringe fields are used: Enge fringe fields, 0.4 m length, 4 th order interpolation off the mid-plane. 4 JB Lagrange - phone meeting - 07/02/14
Outline Enge fringe field fall-offs Change in the lattice Design of the straight magnets Collaboration JB Lagrange - phone meeting - 07/02/14 5
Consequences Length of the fields merge the D magnets in the straight section. Doublet in the straights. Matching section at the ends of the straight to have: No angle at the entrance of the arc α = 0 at the entrance of the arc Increase the m-value in the straight for adjusting the tune. 6 JB Lagrange - phone meeting - 07/02/14
“FODO-LIKE” RFFAG Straight : 175 m, maximum scallop angle : 12 mrad 7 JB Lagrange - phone meeting - 07/02/14
“FODO-LIKE” RFFAG Cell parameters Circular Matching Straight Section Section Section Type FDF FDF Doublet Cell radius/length [m] 17.6 36.2 5 Opening angle [deg] 30 15 5.5 m − 1 k-value/m-value 6.043 25.929 Packing factor 0.92 0.58 0.16 Maximum magnetic field [T] 2.5 3.3 1.5 horizontal excursion [m] 1.3 1.1 0.4 Full gap height [m] 0.45 0.45 0.45 Average dispersion /cell [m] 2.5 1.3 0.18 Number of cells /ring 4 × 2 4 × 2 35 × 2 8 JB Lagrange - phone meeting - 07/02/14
“FODO-LIKE” RFFAG Tune diagram ∆ P = ± 16% P 5 5 5 5 5 5 5 4.9 4.9 4.9 4.9 4.9 4.9 4.9 4.8 4.8 4.8 4.8 4.8 4.8 4.8 4.7 4.7 4.7 4.7 4.7 4.7 4.7 4.6 4.6 4.6 4.6 4.6 4.6 4.6 Q z Q z Q z Q z Q z Q z Q z 4.5 4.5 4.5 4.5 4.5 4.5 4.5 4.4 4.4 4.4 4.4 4.4 4.4 4.4 4.3 4.3 4.3 4.3 4.3 4.3 4.3 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.1 4.1 4.1 4.1 4.1 4.1 4.1 4 4 4 4 4 4 4 7 7 7 7 7 7 7 7.2 7.2 7.2 7.2 7.2 7.2 7.2 7.4 7.4 7.4 7.4 7.4 7.4 7.4 7.6 7.6 7.6 7.6 7.6 7.6 7.6 7.8 7.8 7.8 7.8 7.8 7.8 7.8 8 8 8 8 8 8 8 Q x Q x Q x Q x Q x Q x Q x 9 JB Lagrange - phone meeting - 07/02/14
“FODO-LIKE” RFFAG Magnetic field for P max (+16%) 3 2.5 2 1.5 1 0.5 Bz [T] 0 -0.5 -1 -1.5 -2 -2.5 -3 -3.5 0 50 100 150 200 250 s [m] 10 JB Lagrange - phone meeting - 07/02/14
“FODO-LIKE” RFFAG Beta-functions at matching momentum 40 35 30 25 � [m] 20 15 10 5 0 0 50 100 150 200 250 s [m] Horizontal (plain red) and vertical (dotted purple) betafunctions for half of the ring. 11 JB Lagrange - phone meeting - 07/02/14
“FODO-LIKE” RFFAG Dispersion function at matching momentum 2.5 2 � [m] 1.5 1 0.5 0 0 50 100 150 200 250 s [m] 12 JB Lagrange - phone meeting - 07/02/14
“FODO-LIKE” RFFAG Transverse acceptance 8 8 6 6 4 4 x' [mrad] z' [mrad] 2 2 0 0 -2 -2 -4 -4 -6 -6 -8 -8 -200 -150 -100-50 0 50 100 150 200 -200 -100 0 100 200 z [mm] x [mm] Maximum horizontal stable Maximum vertical stable amplitude over 100 turns amplitude over 100 turns 13 JB Lagrange - phone meeting - 07/02/14
Outline Enge fringe field fall-offs Change in the lattice Design of the straight magnets Collaboration JB Lagrange - phone meeting - 07/02/14 14
Straight magnet design Japanese team: Y. Mori (KURRI), T. Ogitsu (KEK), M. Yoshimoto (JPARC) UK team: C. Booth, P. Smith (Sheffield), N. Marks (STFC) 15 JB Lagrange - phone meeting - 07/02/14
Outline Enge fringe field fall-offs Change in the lattice Design of the straight magnets Collaboration JB Lagrange - phone meeting - 07/02/14 16
Collaboration Manchester University: R. Appleby, S. Tygier, J. Garland. Zgoubi implementation. Error study (FODO & RFFAG rings). DA confirmation. 17 JB Lagrange - phone meeting - 07/02/14
Thank you for your attention JB Lagrange - phone meeting - 07/02/14
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