Overview of Final Focus Optics, Collimeter, Final Doublet and Extraction/Dump

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Overview of Final Focus Optics, Collimeter, Final
Doublet and Extraction/Dump
S.Kuroda ( KEK )

• Final Focus Optics
• Collimeter
• Final Doublet
• Extraction/Dump

MDI meeting at SLAC 1/6/2005
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Final Focus Optics
1. Beam size blow-up due to energy spread(
chromatic effect )
Ds x d s Generally x is large for FF.
(x 103104, mainly from final Q) 2. Chromaticity
correction introducing SX. 3. SX also introduces
geometric aberration(GA). ? Need another SX
and special optics for the GA cancellation
Two Cancellation Scheme Traditional
GA cancelled by -I optics between SXs Local
Correction x corrected locally
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Traditional Optics
TESLA TDR x correction by SX
far upstream of IP Transfer matrix of -I
between SXs h h0 at IP
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Local Correction Optics
? x corrected locally ? GA must be corrected by
optics ? 2nd order h correction also required
NLC BDS
New TESLA BDS
qc0 ?Long drift space for dump
J.Payet, O.Napoly
Collimeter in FFS ?OCT tail folding works good
A.Seryi et al
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Summary of Optics
Recent design tendency is Local Correction
Optics
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Collimeter
Machine( Detector ) Protection Background to
Detector SR of Beam Halo at Final Q
Collimation with spoilerabsorber Off-momentum
Collimation Betatron Collimation Non-linear
field in beam line ?Simulation is required
for performance check
TESLA
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Off-Momentum Collimation
SR protection xLp (hL h)d?lt r Machine
protection
High dispersion low beta section
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Betatron Collimation
High beta dispersion free section Need
iterative collimation for action variable cut
in phase space (Optional use) Periodic
Optics with DY 45 ?emittance measurement
SR by e? of (x, p) at distance L xLp
(in action-angle var.) lt aperture
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Performance of Collimeter
Better collimation performance
in NLC/CLIC ?betad collimation
is better than d beta ?
A.Drozhdin et al
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Other Machine Protection
Magnetic Energy Spoiler(MES) OCTskew SX
Large d beam kicked by OCT
horizontally large Dx in skew SX ?x-y
coupling beam blow-up

• Fast Extraction Line
• Long bunch spacing in
• Cold machine
• much enough time to
• detect error
• and fire kicker

TESLA
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Other Issue for Collimeter
Spoiler Absorber Wake field Heat load
?survivability/life time
survivable spoiler A.Seryi
Muon collimation
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Final Doublet
Crossing angle qc L is the critical parameters
for design Outgoing beam go inside or outside of
the bore
Normal Electric Magnet
Established technology Heat load?cooling
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Super-conducting Magnet
High gradient/Low power consumption Large
bore radius ( common with outgoing
beam ) Vibration? ? He flow in cryostat
LHC
Various type of SC magnets are proposed
Compact SC magnet
Small bore/double aperture
Flat inner tube?
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Permanent Magnet
High gradient w/o power consumption
Compact/small bore Adjustability/tunability
?Hybrid Field compensation mover
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Summary for Final Doublet
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Beam Extraction/Dump
Charged beam extraction Boundary
condition by qc and L Machine
protection by beamstrahlung g Dump for
beamstrahlung Material of the dump for e
beamstrahlung