EMMA injection & extraction Takeichiro Yokoi(Oxford University)

EMMA injection & extraction

Takeichiro Yokoi(Oxford University)

Injection and extraction with linear model

Presumed conditions….

Kicker field :≤0.6kgauss(bipolar) Kicker length : 0.1m Beam emittance: 3πmm (normalized) Energy: 10~20MeV(1MeV step) 4 operation mode (latest lattice:parallel elements) 070221b,c,d,e Tracking code (ZGOUBI: sharp edge field) Septum boundary: +5mm from the outer-most beam envelope

Lattices …

∆xQF ∆xQD

B1QD

(T/m)

B1QF

(T/m)

∆xQD

(mm)

∆xQF

(mm)

070221b -4.704 6.695 34.048 7.514

070221c -4.126 6.108 39.195 8.171

070221d -3.597 5.230 46.532 9.535

070221e -3.764 6.553 40.797 7.684

Horizontal tune

Setup of tracking study

QF0 QF1 QF2

Beam

QD0 QD1 QD2

Kicker KickerSeptum

QF0QF1QF2 QD0QD1QD2

Kicker Kicker

Septum

injection

extraction

* Backtracking from CO

*Beam position was monitored at the center of each magnet and drift space

Beam distribution at septum (injection)

∆x’:270mrad

∆x:4mm70221b

Beam envelope at magnet center

QD1

QD2

QF1

QF2

70221b 70221b

70221b 70221b

70221c 70221c

70221c 70221c

70221d 70221d

70221d 70221d

70221e 70221e

70221e 70221e

xmax

xmin

Magnet centerQF requires large good field region (max 80mm)

Large orbit swing comes form 10MeV

QD1 requires a little larger good field region than that inscribed. (max 60mm)

±32mm

±56mm

*Beam position at the center of magnet is plotted for the orbit inside of target box

Beam envelope at magnet center (2)

QD1

QD2

QF1

QF2

70221b 70221b

70221b 70221b

70221c 70221c

70221c 70221c

70221d 70221d

70221d 70221d

70221e 70221e

70221e 70221e

xmax

xmin

Magnet center

±32mm

±56mm

10MeV of 70221b enlarges the target box…. Excluding it, orbit swing decreases.

Injection energy and GFR of QF

GFR 70221b 70221c 70221d 70221e

±32mm 15MeV~ 15MeV~ 14MeV~ 13MeV~





Beam distribution at septum (extraction)

∆x’:40mrad

∆x:2.5mm70221b

Beam envelope at magnet center

QD1

QD2

QF1

QF2

70221b 70221b

70221b 70221b

70221c 70221c

70221c 70221c

70221d 70221d

70221d 70221d

70221e 70221e

70221e 70221e

xmax

xmin

Magnet centerQF1 requires large good field region (max 49mm)

Large orbit swing comes form 10MeV

QD1 requires a little larger good field region than that inscribed. (max 60mm)

If larger target box size is accepted, except 10MeV of 70221c and d, extraction is possible with present good field region

±32mm

±56mm

Beam position at the center of magnet is plotted for the orbit inside of target box

Injection and extraction with TOSCA 3D field

Injection and extraction orbits are one-pass orbits. For such orbits, what is important is bending component, and requirement to quadrupole component might be released.

Magnet & cell modeling

QD Pole width:100mm Xt: 15mm

QF Pole width:73mm Xt: 11mm

•Aperture of clamp is 45° rotated square( side: 14cm:D, 10cm:F)

•Vertical symmetry is introduced

•Optimized mesh size obtained through individual magnet modeling is used

•As typical lattices, 4 lattices are modeled (070221b,c,d,e)

GFR:±36mm

GFR:±26mm

Parameterization of current

2.0cm

QF

QD

+

As a nominal focusing power, focusing power of region 2 was taken

Comparison with baseline design

Baseline (By. S. Berg)

Tracking

070221b: D 4680 AT, F 2960AT 070221c: D 4000AT, F 2640AT070221d: D3400AT, F 2080AT

Except the vertical tune of low energy, the results show so so good agreement with the design

Map geometry for injection study

QD

QF clamp

clamp

Insertion

insertion

Putting the map boundary at 5.5cm from the magnet end, field error caused by the map geometry is less than 0.2%

map

map

8.5714˚

±65mm

X

Y

55mm 55.76mm

8.5714˚

288mm

Map geometry(2)

Field map Mesh size X: 1mm,Y: 1mm, Z: 1mm

(rough optimization was carried out)

Drift space for adjustment51.891mm

54.589mm

Center of long drift

83mm 57mm 61mm 87mm

Beam distribution at septum (injection)

70221b

septum

5mm

140mrad

septum

For 10, 11MeV of 70221b, 10MeV of 70221c, there is no injection orbit

Beam envelope in magnet (injection)

QF1

Required GFR(±32mm)

70221b

70221c

QD2

70221b

70221c

70221d

QD1


XmaxXmin

70221b

70221c

70221d

QF2

70221b

70221c

70221d 70221d

Center of magnetInjection orbit outside GFR anyhow exists (matching problem remains)

Beam distribution at septum (extraction)

70221b

Septum septum

50mrad.

3mm

Beam envelope in magnet (extraction)

QF1


70221b

70221c

70221d

QD1


XmaxXmin

70221b

70221c

70221d

QF2

70221b

70221c

70221d

QD2

70221b

70221c

70221d

Center of magnet Extraction orbit outside GFR anyhow works

Remaining work ….

Optimize current setting

Include septum into tracking (matching)

Check the remaining 5 operation modes (70221e,f,g,h,l)

Confirm the result with final magnet design

Summary

Tracking study with the hard edge model indicates that orbit swing of injection and extraction orbit goes beyond the present required good field region of QF. Tracking with 3d model shows extraction and extraction orbits outside of good field region anyhow work, but threre are missing injection conditions ( 10,11MeV of 70221b, 10MeV of 70221c), and beam distribution at septum is broader than that of extraction.

Any possibilities to reverse the magnet sequence ??

EMMA injection & extraction Takeichiro Yokoi(Oxford University)

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