Update on RFFAG ring for STORM JB. Lagrange, J. Pasternak Imperial - - PowerPoint PPT Presentation

Update on RFFAG ring for νSTORM

• JB. Lagrange, J. Pasternak

Imperial College

JB Lagrange - phone meeting - 07/02/14

Enge fringe field fall-offs Change in the lattice Design of the straight magnets Collaboration

Outline

2

JB Lagrange - phone meeting - 07/02/14

Enge fringe field fall-offs Change in the lattice Design of the straight magnets Collaboration

Outline

3

JB Lagrange - phone meeting - 07/02/14

Enge fringe field fall-offs

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To validate the dynamical aperture, more realistic fringe fields are used: Enge fringe fields, 0.4 m length, 4th order interpolation off the mid-plane.

JB Lagrange - phone meeting - 07/02/14

Enge fringe field fall-offs Change in the lattice Design of the straight magnets Collaboration

Outline

5

JB Lagrange - phone meeting - 07/02/14

Consequences

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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.

JB Lagrange - phone meeting - 07/02/14

“FODO-LIKE” RFFAG

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Straight: 175 m, maximum scallop angle: 12 mrad

JB Lagrange - phone meeting - 07/02/14

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Cell parameters

“FODO-LIKE” RFFAG

Circular Matching Straight Section Section Section Type FDF FDF Doublet Cell radius/length [m] 17.6 36.2 5 Opening angle [deg] 30 15 k-value/m-value 6.043 25.929 5.5 m−1 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

JB Lagrange - phone meeting - 07/02/14

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Tune diagram ∆P

P = ±16%

“FODO-LIKE” RFFAG

4 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 5 7 7.2 7.4 7.6 7.8 8

Qz Qx

4 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 5 7 7.2 7.4 7.6 7.8 8

Qz Qx

4 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 5 7 7.2 7.4 7.6 7.8 8

Qz Qx

4 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 5 7 7.2 7.4 7.6 7.8 8

Qz Qx

4 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 5 7 7.2 7.4 7.6 7.8 8

Qz Qx

4 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 5 7 7.2 7.4 7.6 7.8 8

Qz Qx

4 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 5 7 7.2 7.4 7.6 7.8 8

Qz Qx

JB Lagrange - phone meeting - 07/02/14

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Magnetic field for Pmax (+16%)

“FODO-LIKE” RFFAG

• 3.5
• 3
• 2.5
• 2
• 1.5
• 1
• 0.5

0.5 1 1.5 2 2.5 3 50 100 150 200 250 Bz [T] s [m]

JB Lagrange - phone meeting - 07/02/14

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Horizontal (plain red) and vertical (dotted purple) betafunctions for half of the ring.

Beta-functions at matching momentum

“FODO-LIKE” RFFAG

5 10 15 20 25 30 35 40 50 100 150 200 250 [m] s [m]

JB Lagrange - phone meeting - 07/02/14

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Dispersion function at matching momentum

“FODO-LIKE” RFFAG

0.5 1 1.5 2 2.5 50 100 150 200 250 [m] s [m]

JB Lagrange - phone meeting - 07/02/14

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Maximum horizontal stable amplitude over 100 turns Maximum vertical stable amplitude over 100 turns

Transverse acceptance

“FODO-LIKE” RFFAG

• 8
• 6
• 4
• 2

2 4 6 8

• 200
• 100

100 200 x' [mrad] x [mm]

• 8
• 6
• 4
• 2

2 4 6 8

• 200
• 150
• 100-50 0 50 100

150 200 z' [mrad] z [mm]

JB Lagrange - phone meeting - 07/02/14

Enge fringe field fall-offs Change in the lattice Design of the straight magnets Collaboration

Outline

14

JB Lagrange - phone meeting - 07/02/14

Straight magnet design

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Japanese team: Y. Mori (KURRI), T. Ogitsu (KEK),

• M. Yoshimoto (JPARC)

UK team: C. Booth, P. Smith (Sheffield), N. Marks (STFC)

JB Lagrange - phone meeting - 07/02/14

Enge fringe field fall-offs Change in the lattice Design of the straight magnets Collaboration

Outline

16

JB Lagrange - phone meeting - 07/02/14

Collaboration

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Manchester University: R. Appleby, S. Tygier,

• J. Garland.

Zgoubi implementation. Error study (FODO & RFFAG rings). DA confirmation.

JB Lagrange - phone meeting - 07/02/14

Thank you for your attention