A.Poklonskiy (SPbSU, MSU), D.Neuffer (FNAL) C.Johnstone (FNAL), M.Berz (MSU), K.Makino (MSU)
Update on ILC ML Lattice Design Alexander Valishev, for the FNAL LET group FNAL AP Dept. Meeting...
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Transcript of Update on ILC ML Lattice Design Alexander Valishev, for the FNAL LET group FNAL AP Dept. Meeting...
Update on ILC ML Lattice Design
Alexander Valishev,for the FNAL LET group
FNAL
AP Dept. Meeting March 7, 2007
2APD meeting March 7, 07
ML Lattice design
Outline
• Basic layout• Curvature implementation• Matching• Summary and problems
3APD meeting March 7, 07
ML Lattice design
Lattice Design
• Defined by cryo segmentation• Versions of segmentation
» 8-8-8 scheme, May 31 2006» 9-8-9 scheme, Dec 28 2006
• Basic segmentations:
Main Linac
RF Unit
Cryogenic Unit
APD meeting March 7, 07
ML Lattice design
May 31 revision (v.3) 8-8-8
5APD meeting March 7, 07
ML Lattice design
Curvature Implementation
• Beam line geometry definition differs for MatLIAR/Lucretia and MAD.
• A method to have one set of decks and still be able to work with two codes was proposed by M.Woodley:» One common XSIF file, defining beam line, all common
elements, and ‘KINK’ elements at the ends of cryomodules.
» Two different files defining KINK elements to be used in MatLIAR and MAD. One of the files is called from the main file depending on the software used.
» Beam trajectory in both cases is changed by VKICK elements
• Another approach is to use vertical SBENDs» In this case one deck is compatible with both codes
6APD meeting March 7, 07
ML Lattice design
Curvature Implementation
• GKICK, Multipole
• SBEND
7APD meeting March 7, 07
ML Lattice design
Implementation of ‘KINKs’
• MatLIAR/Lucretia: Thin ‘dispersion-free kick’ GKICK, which pitches the coordinate system.
• MAD: Combination of» General thin multipole n=0, changes both
the beam trajectory and the coordinate system
» VKICK of the opposite sign
8APD meeting March 7, 07
ML Lattice design
ILC2006e (8-8-8) Lattice -functions
9APD meeting March 7, 07
ML Lattice design
ILC2006e Orbit
10APD meeting March 7, 07
ML Lattice design
ILC2006e Dispersion
11APD meeting March 7, 07
ML Lattice design
Emittance Preservation LIAR Simulation: CURVED LINAC: ILC BCD-Like LATTICE
Orb
it a
t th
e Y
CO
Rs
(m
)
Perfect Lattice - No misalignments
Zoom
No
rma
lize
d E
mit
tan
ce
(n
m)
Static Tuning: Dispersion Matched Steering (DMS) - Misalign the beamline components and perform the steering
Average of 50 machines
Straight
Curved
Co
rre
cte
d n
orm
ali
zed
em
itta
nc
e
(nm
)
Mean: 5.0 ± 0.4 nm
90%: 8.7 nm
Laser Straight
Mean: 5.3 ± 0.5 nm
90%: 9.5 nm
Curved
Distribution of emittance growth for 50 seeds
BPM index
BPM index
12APD meeting March 7, 07
ML Lattice design
Summary
• ML lattices based on two cryogenic layouts have been developed
• Two versions of ILC2006e (8-8-8) ML lattice (GKICK/MULT and SBEND) were studied» Both versions work well in Lucretia and show similar
emittance growth» It was decided at the Daresbury meeting in January
that only GKICK/MULT lattice will be supported
• Static alignment simulations show acceptable emittance growth in the curved ML lattice
• Dynamic simulations in progress
13APD meeting March 7, 07
ML Lattice design
Problems
• Create set of decks suitable for simulations of bunch propagation from RTML to the end
• Improve dispersion matching between curved and straight sections» The way it was implemented in ILC2006e
suggests large orbit kinks with angles of ~3e-4» At 250 GeV, this leads to energy losses of
100MeV and synchrotron radiation power of 4kW» One possible solution – make smooth transition
from curved to straight beam line.