overview of final focus optics, collimeter, final doublet and extraction/dump
DESCRIPTION
Overview of Final Focus Optics, Collimeter, Final Doublet and Extraction/Dump. Final Focus Optics Collimeter Final Doublet Extraction/Dump. S.Kuroda ( KEK ). MDI meeting at SLAC 1/6/2005. Final Focus Optics. 1. Beam size blow-up due to energy spread( chromatic effect ) - PowerPoint PPT PresentationTRANSCRIPT
Overview of Final Focus Optics, Collimeter, Final Doublet and E
xtraction/Dump
• Final Focus Optics• Collimeter• Final Doublet• Extraction/Dump
S.Kuroda ( KEK )
MDI meeting at SLAC 1/6/2005
Final Focus Optics1. Beam size blow-up due to energy spread( chromatic effect ) Generally is large for FF. ( =103~104, 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” : corrected locally
Traditional Optics
TESLA TDR
correction by SX far upstream of IP Transfer matrix of -I between SXs = ’=0 at IP
Local Correction Optics
[J.Payet, O.Napoly]
NLC BDS
[A.Seryi et al]
New TESLA BDS
corrected locallyGA must be corrected by optics 2nd order correction also required
c=0 Long drift space for dump
Collimeter in FFSOCT tail folding works good
Summary of Optics
‘Traditional Optics’ ‘Local Correction Optics’
• Comprehensive
• Tested at FFTB
• Wide momentum band width
• Expandability to high energy
• Compact beam line
Recent design tendency is ‘Local Correction Optics’
CollimeterMachine( Detector ) ProtectionBackground to Detector SR of Beam Halo at Final Q
Collimation with spoiler+absorber Off-momentum Collimation Betatron CollimationNon-linear field in beam line Simulation is required for performance check
[TESLA]
Off-Momentum Collimation
SR protection x+Lp = (+L ’)< r
Machine protection
High dispersion & low beta section
Betatron Collimation
High beta & dispersion free sectionNeed iterative collimation for action variable cut in phase space(Optional use) Periodic Optics with = 45° emittance measurement
2Jβ
−Lα +β( )cosθ+Lsinθ( )≤2J −Lα +β( )
2+L2( )
β
SR by e of (x, p) at distance L x+Lp=
(in action-angle var.)< aperture
Performance of Collimeter
Better collimation performance in NLC/CLICbeta+ collimation is better than +beta ?
[A.Drozhdin et al]
Other Machine Protection Magnetic Energy Spoiler(MES) OCT+skew SX Large beam kicked by OCT horizontally large x in skew SX x-y coupling & beam blow-up
Fast Extraction Line Long bunch spacing in Cold machinemuch enough time to detect error and fire kicker
[TESLA]
Other Issue for Collimeter
Spoiler & Absorber Wake field Heat load survivability/life time
Muon collimationsurvivable spoiler [A.Seryi]
Final Doublet
Normal Electric Magnet• Established technology• Heat loadcooling
Crossing angle c & L* is the critical parameters for designOutgoing beam go inside or outside of the bore
Super-conducting Magnet• High gradient/Low power consumption• Large bore radius ( common with outgoing beam )• Vibration? He flow in cryostat
Various type of SC magnets are proposed
LHC
Small bore/double aperture
Compact SC magnet
Flat inner tube
Permanent Magnet
• High gradient w/o power consumption • Compact/small bore • Adjustability/tunability
Hybrid Field compensation mover
Summary for Final Doublet
EM SC PM
• Established technology
• Power consumption
cooling
• High gradient
• Large bore
• Vibration?
• High gradient • Compact/small bore • Adjustability/tunabilit
y
Beam Extraction/Dump
• Charged beam extraction Boundary condition by c and L* Machine protection by beamstrahlung • Dump for beamstrahlung • Material of the dump for e± & beamstrahlung