MICE Demonstration of Ionization Cooling Update JB. Lagrange, J. - - PowerPoint PPT Presentation

MICE Demonstration of Ionization Cooling Update

• JB. Lagrange, J. Pasternak
• n behalf of the MICE collaboration

1

JB Lagrange - MAP meeting - June 2015

Demo lattice Optimization Results Summary and future plans

Outline

2

JB Lagrange - MAP meeting - June 2015

Demo lattice Optimization Results Summary and future plans

Outline

3

JB Lagrange - MAP meeting - June 2015

Demo Lattice

4

JB Lagrange - MAP meeting - June 2015

Radiation shutter and movable secondary LiH absorber.

5

Lead shutter Vacuum chamber LiH Secondary absorber Rails

JB Lagrange - MAP meeting - June 2015

6

Coil currents (6 mm, 200 MeV)

Coil

Demo lattice

Nominal values (step V)

Upstream E2

+253.00 255.46

Upstream C

+274.00 288.27

Upstream E1

+234.00 239.37

Upstream M2

+203.13 290.69

Upstream M1

+240.61 274.34

Upstream AFC1

+77.86 245.65

Downstream AFC1

+77.86 245.65

Upstream AFC2

• 72.94

245.65

Downstream AFC2

• 72.94

245.65

Downstream M1

• 218.39

274.34

Downstream M2

• 187.68

290.69

Downstream E1

• 234.00

239.37

Downstream C

• 274.00

288.27

Downstream E2

• 253.00

255.46

JB Lagrange - MAP meeting - June 2015

7

Magnetic field

z [m] Bz [T]

AFC absorber AFC

Demo Lattice

JB Lagrange - MAP meeting - June 2015

Initial beam

8

Pure muon beam, ~10 000 particles Position: before first plane upstream tracker (after diffuser) Gaussian distribution Normalised rms longitudinal emittance = 20 mm Normalised rms transverse emittance = 6 mm

Cuts

PID cut Transmission cut Radial cut r < 200 mm, at first and last plane.

JB Lagrange - MAP meeting - June 2015

9

Transverse beta

Old reference lattice

z [m] Beta [mm]

AFC absorber AFC

JB Lagrange - MAP meeting - June 2015

10

4D emittance

z [m] 4D Emit. [mm]

AFC absorber AFC

5.5% cooling

Old reference lattice

JB Lagrange - MAP meeting - June 2015

11

6D emittance

z [m] 6D Emittance

AFC absorber AFC

Old reference lattice

JB Lagrange - MAP meeting - June 2015

Demo lattice Optimization Results Summary and future plans

Outline

12

JB Lagrange - MAP meeting - June 2015

Optimization

13

Optimization through 2 parameters

• phase advance of the channel
• Strength of the focusing elements

JB Lagrange - MAP meeting - June 2015

Phase advance

14

Phase advance is computed from the last plane of the upstream tracker to the first plane of the downstream tracker. Different phase advances for different lattices show the same effect: phase advance should stay between half-integer resonances. 630 deg. (1.75×360 deg.) seems to be the optimum:

• Best momentum acceptance,
• smallest non-linear effects (chromatic mismatch

downstream minimized).

JB Lagrange - MAP meeting - June 2015

Focusing strength

15

Once the phase advance and values of beta at the absorbers is decided, only free parameters are the length between SS and Cavity module, the length between the AFCs.

• Different cases show that M1 should be minimized to

limit non-linearities. so the length SS-Cavity should be kept minimum (case of the reference lattice)

• Different cases show that large values of beta in the

FC trigger strong non-linearities.

• ➯ Optimum of the length AFC-AFC.

JB Lagrange - MAP meeting - June 2015

AFC - AFC Length

16

Different lengths have been tested L0 (old reference lattice) L1 (L0 - 376.5 mm) L2 (L0 - 187.0 mm) L3 (L0 - 93.5 mm) L4 (L0 - 46.7 mm)

• Best performances for length L0 & L4.
• ➯ L4 seems to be the best lattice.

JB Lagrange - MAP meeting - June 2015

Demo lattice Optimization Results Summary and future plans

Outline

17

JB Lagrange - MAP meeting - June 2015

18

Coil currents (6 mm, 200 MeV)

Coil

Optimized lattice

Old reference lattice

Upstream E2

+253.00 +253.00

Upstream C

+274.00 +274.00

Upstream E1

+234.00 +234.00

Upstream M2

+158.81 +203.13

Upstream M1

+239.68 +240.61

Upstream AFC1

+76.39 +77.86

Downstream AFC1

+76.39 +77.86

Upstream AFC2

• 71.95
• 72.94

Downstream AFC2

• 71.95
• 72.94

Downstream M1

• 218.45
• 218.39

Downstream M2

• 152.20
• 187.68

Downstream E1

• 234.00
• 234.00

Downstream C

• 274.00
• 274.00

Downstream E2

• 253.00
• 253.00

JB Lagrange - MAP meeting - June 2015

19

Magnetic field

z [m] Bz [T]

AFC absorber AFC

Optimized Lattice

JB Lagrange - MAP meeting - June 2015

20

Transverse beta

z [m] Beta [mm]

AFC absorber AFC

Optimized lattice

JB Lagrange - MAP meeting - June 2015

21

4D emittance

z [m] 4D Emit. [mm]

AFC absorber AFC

5.6% cooling

Optimized lattice

JB Lagrange - MAP meeting - June 2015

22

6D emittance

z [m] 6D Emittance

AFC absorber AFC

Optimized lattice

JB Lagrange - MAP meeting - June 2015

Demo lattice Optimization Results Summary and future plans

Outline

23

JB Lagrange - MAP meeting - June 2015

Summary

Optical parameters have been studied and optimization

• f the length have been done.

Best performance for length L4 (5.6% 4D cooling).

24

JB Lagrange - MAP meeting - June 2015

Future plans

Update of the geometry with latest information from step IV. Study of different emittances for 140 MeV/c, 200 MeV/c, 240 MeV/c. Paper including all settings to be finalized soon.

25

JB Lagrange - MAP meeting - May 2015

Thank you for your attention

26