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Overview of Beam Delivery System. Final Focus Optics Collimator Final Doublet Extraction/Dump Others. S.Kuroda ( KEK ). MDI meeting at SLAC 1/6/2005. Final Focus Optics. 1. Beam size blow-up due to energy spread( chromatic effect ) =
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Overview of Beam Delivery System • Final Focus Optics • Collimator • Final Doublet • Extraction/Dump • Others S.Kuroda ( KEK ) MDI meeting at SLAC 1/6/2005
Final Focus Optics 1. 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 corrected locally GA must be corrected by optics 2nd order correction also required NLC BDS New TESLA BDS c=0 Long drift space for dump [J.Payet, O.Napoly] Collimator in FFS OCT tail folding works good [A.Seryi et al]
Summary of Optics Recent design tendency is ‘Local Correction Optics’
Collimator Machine( Detector ) Protection Background to Detector SR of Beam Halo at Final Q Collimation with spoiler+absorber Energy Collimation Betatron Collimation Non-linear field in beam line Simulation is required for performance check [TESLA]
Energy Collimation SR protection x+Lp = (+L ’)< r Detector protection Background study High dispersion & low beta section
Betatron Collimation High beta & dispersion free section Need iterative collimation for action variable cut in phase space (Optional use) Periodic Optics with = 45° emittance measurement SR by e of (x, p) at distance L x+Lp= (in action-angle var.) < aperture
Performance of Collimator [A.Drozhdin et al] Better collimation performance in NLC/CLIC (beta+collimation+local correction FF is better than (+beta)collimation+traditional FF ?
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 machine • much enough time to detect error and fire kicker [TESLA]
Other Issue for Collimator Spoiler & Absorber Wake field Heat load survivability/life time Fast emergency extraction line is necessary survivable spoiler [A.Seryi] Muon collimation
Final Doublet [T.Mihara,O.Napoly 1st ILCWS] Crossing angle c & L* is the critical parameters for design Outgoing beam go inside or outside of the bore Normal Electric Magnet • Established technology • Heat loadcooling
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
Permanent Magnet • High gradient w/o power consumption • Compact/small bore • Fine tuning for temperature/ rad. Damage Adjusting for big E change( e.g. Z-pole ) Hybrid Field compensation mover
Beam Extraction/Dump • Charged beam extraction Boundary condition by c and L* Diagnostic section 1) Energy 2) Polarization …… Chicane for photon separation 2nd focusing point for Laser collision Machine protection by beamstrahlung • Dump for beamstrahlung? • Background( neutron ) study from the extraction/dump • ……
TESLA Extraction optics Head-on scheme Irradiation of septum magnet No beam diagnostic after collision is considered Beam size when no collision
GLC Extraction [K.Kubo] Geometry 7mrad crossing Superconducting final Q is assumed (out-going particle goes inside of Q ) Diagnostic section is considered. Transmission and background study need more to do optics
Extraction for 20mrad crossing [Y.Nosochkov] 2nd focal point in vertical chicane for beam diagnosis Good transmission for disrupted beam
11 mrad NLC-style Big Bends 200 m drifts NLC BSY dump lines IR2 2 mrad Andrei’s 20 mrad ILC FF (x 4) IR1 20 mrad IP separation: 150 m (Z), 22 m (X) Yuri’s ILC 20 mrad dump lines Others • Straw-man layout for ILC BDS [M.Woodley] Design done except Pre-IP E-spectrometer FEXL Extraction for 2mrad
Total field with and w/o antisolenoids LD model, q = 20 mrad LD model, q = 0 With antisolenoids and linear knobs, dsy = 0.9% • Solenoid Field Compensation [Y. Nosochkov, A. Seryi] Solenoid field at FD beam size blow-up ( independent on crossing angle ) Anti-solenoid compensation Anti-solenoids provide good compensation, and it is considered as a part of detector More effective with skew Q