RTML ( Except Bunch Compressor )
-
Upload
wilma-beard -
Category
Documents
-
view
33 -
download
2
description
Transcript of RTML ( Except Bunch Compressor )
RTML( Except Bunch Compressor )
Parameters and LayoutDiagnostics and Beam TuningAccelerator PhysicsAccelerator Components
S.Kuroda ( KEK )
Beam Parameters
Layout
Extraction from the DR ( ERTL/PRTL )
No vertical dogleg in ERTL because of the DR vertical position
Return Line ( ELTL/PLTL )• Following the earth’s curvature in ML tunnel
V correctors in each QV dispersion matching by v correctors at both ends
Return Line ( ELTL/PLTL )(2)• Horizontal dogleg at the junction of ML and
BDS, which is different in ELTL and PLTL due to positron target
Geometry of the dog-leg defined in document EDMS: D*0969955
Return Line ( ELTL/PLTL )(3)Mountain topography
Flat topography
Turn Around
Spin Rotator
H-dogleg
V-dogleg
z
x
z
y
• Horizontal dogleg• Vertical dogleg to adjust
elevation to ML• 180-8 deg. turn around with
dispersion matching( 8 deg. is needed for spin rotator )
• Bunch by bunch feed-forward. Time delay is 600 ns.
Spin Rotator
Diagnostics• Cavity BPM • Laser Wire for emittance measurement
Beam Tuning
• Dispersion Correction– Normal and skew Q in ERTL/PRTL in hx region• In pairs with –I --> No introduction of coupling
– Normal Q in h/v dogleg of Turn Around• Coupling correction– 4 skew Qs in zero dispersion region downstream
of ERTL/PRRTL and Spin Rotator
Beam Physics Issues
• ISR
Vertical emittance growth is negligible • Beam-Ion instability ( L.Wang, et al )– < 2mPa
Horizontal emittance growth
Arc( RTL ) 90nm (1.1 % )
Turn-around 430nm ( 5.4 % )
Beam Physics Issues (2)
• Stray Field– Tolerance ( K.Kubo ) • 2nT for orbit jitter of 0.2sy
– This can be corrected by fast feed-forward
• Higher for emittance growth
Stray Field ( Measurement )
N.Solyak 2011
Beam Physics Issues (3)
• Halo Formation from Scattering( S.M.Seletskiy )– 2mPa 2e-6 of beam intensity < tolerance of 1e-5
• Space-Charge Effect– Incoherent space charge tune shift is O(0.15) in v– To be studied
Beam Physics Issues (4)
• Emittance Preservation ( A. Latina )
Accelerator Components• Magnets
• Vacuum– Requirement: < 2mPa
Summary and Work to Be Done
• Lattice and optics design is almost done in TDR– Must be re-designed when the accelerator length is
adjusted. • A few things of accelerator physics issue to be
done?– Simulation study should be continued( emittance, ..)– Stray field measurement should be continued.– Space charge tune shift– …