Magnet Lattice for MAXIV Storage Ring

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Magnet Lattice for MAX-IV Storage Ring
Hamed Tarawneh, Mikael Eriksson, Lars-Johan
Lindgren and Sverker Werin
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Magnet Lattice for MAX-IV Storage Ring
1- Introduction. 2- Design Philosophy. 3-
Dynamic Properties of MAX-IV Lattice. 4- Magnet
System. 5- Soft End Magnet.
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MAX-lab accelerators
MAX I 500MeV
MAX III 700 MeV
Linac injector
MAX II 1.5 GeV
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Why MAX-IV ?.
The MAX-IV facility is planned to be the
successor of the present MAXlab facility
offering high brilliance radiation, spontaneous
as well as coherent, over a wide spectral region.
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Design Philosophy -Small Emittance ( e 1
nm.rad ). ? Large number of
magnets. -Small gap superconducting undulators
( 5mm) ?Small gap in the magnet
elements . -Double RF system. ?
longer lifetime.
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MAX-IV Machine Parameters
Ring circumference (m)
287 Operating energy (GeV)
3
Circulating current (A)
0.5
Emittance (nm rad)
1.2 Emittance with 4
wigglers (nm.rad) 0.86
Horizontal Tune
26.6
Vertical Tune 9.6
Periodicity
12
Nr. of straight sections 10
Length of
straight section (m) 4.6
Beam 1/e lifetime Touschek (h) 18
El scattering (h)
131
Bremsstrahlung (h) 195
Total (h)
14.6 RF (MHz)
100
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Machine functions of the MAX IV
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Beam cross sections at the MAX IV
?x 97 ?m ?y 4.8 ?m
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Phase Space and Dynamic Aperture -The aperture
of an accelerator is not only defined by the
vaccum chamber but also by the EM field which
guide and accelerate the beam. -The inclusion of
sextupolar fields reduce the maximum stable
oscillation for the particles (Dynamic
Aperture).
Dynamic Aperture gt Physical Aperture
Dynamic Aperture
Vacuum chamber
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Tune Variation -Sextupole fields introduce
chromatic and geometric aberrations. -Sextupole
component in dispersion-free section and Octupole
component were introduced to minimise tune shift
with energy deviation and oscillation
amplitude. -Particles get lost as thier tunes
sample resonance conditions.
With energy deviation (Chromatic Abberation)
With oscillation amplitude (Geometric Abberation)
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• Magnet System
• -A small emittance lattice calls for a large
  number of magnet elements.
• The small aperture size allows for strong
  multipole magnet.
• The magnets are machined from a solid iron blocks
  (MAX-III type).

One unit cell of the lattice with Dipole, two
quadrupoles and two sextupoles magnets.
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Unit Cell Bending Magnet
2.2 cm

• Field Quality ?B /B 1 x 10-4
• ?g /g 1 x 10-3
• Ampere-turn, NI 9000
• Field below 1.4 T in the magnet yoke

29cm
30cm
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Unit Cell Quadrupole Magnet

• Field Quality ?g /g 5 x10-4
• Ampere-turn, NI 1800
• Field below 1 T in the magnet yoke

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Soft End Magnet The synchrotron radiation power
hitting the cold bores is restricted by the
introduction of soft end magnet preceding the SC
undulator.
SR Power 1/?
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Soft End Magnet Parameters

• Distributing the gradient along both magnets.
• ? Adv. reducing the field in the inner
  poletip.

0.75 m
Coil
Floating Pole
1.16 T
0.2 T
1
2
e-beam
B1g1 B2g2 a NI
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Soft End Magnet
Floating Pole
Bottom Half of the Magnet
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Soft End Magnet
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Field Distribution (Transversely)
-Magnetic Field from the bulk multipoles
Field distribution in the magnet midplane
Bulk Multipoles contents
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Field Distribution (Longitudinally)
Field map along the model magnet
B, Tesla
Transition Region
x, mm
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Conclusions The chosen lattice with a small
emittance is able to provide good dynamic
aperture and momentum acceptance.