Electron Source Configuration Axel Brachmann - SLAC - Jan , KEK GDE meeting International Linear Collider at Stanford Linear Accelerator Center

Layout as defined in the Baseline Configuration Document Positron-style room- temperature accelerating section diagnostics section standard ILC SCRF modules sub-harmonic bunchers + solenoids laser E= MeV Additional Responsibilities:  Injector  Damping ring transfer  SPIN control (LINAC longitudonal  DR vertical) International Linear Collider at Stanford Linear Accelerator Center

Overview  Laser System and (laser) optical transfer  see Snowmass ’05  Polarized Gun  Bunching Section  NC pre-accelerator  SC e- Injector LINAC  Basic component count  Length estimates References: - TESLA TDR - A. Curtoni, M. Jablonka; Study of the TESLA preaccelerator for the polarized beam, TESLA International Linear Collider at Stanford Linear Accelerator Center

BPM Load-lock chamber connects here Ion Pump RGA High voltage insulator e - beam laser beam Magnetic lens 120 kV DC Gun – Baseline Design is SLC Gun Approximate location of cathode Leak valve Load-lock and cesiator on other side International Linear Collider at Stanford Linear Accelerator Center

Loadlock System for Cathode Preparation and Installation International Linear Collider at Stanford Linear Accelerator Center

ILC DC Gun Design  SLC gun is baseline 120 kV, 1.7 MV/m at Cathode Possible higher gradient, eg. at Cornell, Jefferson Lab, Nagoya New electrode materials, cesiation schemes  Polarized RF gun R&D International Linear Collider at Stanford Linear Accelerator Center

Bunching Section  SHB Normal conducting sub-harmonic bunching section Focusing by solenoidal field Scaling from TTF results in following parameters : Distance between sub-harmonic buncher cavities: 200 cm Bunch compression: 97 o rms at entrance to second SHB cavity, and 30 o rms at buncher entrance Distance to buncher: 38 cm  Buncher 2 cavities (5 cell) separated by λ/2 (115.3 mm);  =1 Structure 14.8 MV/m (simulations with 12 MV/m) 12 MeV beam energy after bunching Cavity #F [MHz]Voltage [kV] Rs [M  ] Q0Q0 P [W] 1108 (1/12) * (1/3) * International Linear Collider at Stanford Linear Accelerator Center

NC Pre-Accelerator Energy from 12 MeV  ~ MeV Positron style room temperature accelerating section 17 cell cavities, one pair  31 MeV energy gain using 10 MW klystron Number of pairs must be selected –2 pairs  ~ 76 MeV, 0.28 mm.mrad (un. Emitt.) –3 pairs  ~ 100 MeV, 0.2 mm.mrad (un. Emitt.) 1 triplet between pairs 2 triplets to match to SC LINAC module Spectrometer arm for independent tuning International Linear Collider at Stanford Linear Accelerator Center

500 MeV SC LINAC and 5 GeV e - Injector LINAC  STEP 1 Add ~ 424 MeV Two standard SC LINAC modules of 12 cavities each Gradient: E acc = 17.8 MV/m Lower energy requires doublets instead of triplets  STEP 2 Energy gain to 5 GeV by 18 standard cryomodules Gradient: E acc = 20 MV/m International Linear Collider at Stanford Linear Accelerator Center

Instrumentation  Special diagnostics: Gun diagnostics Vacuum Dark current QE diagnostics  Integrated into gun design Faraday cup Mott polarimeter  BPM’s, Toroids, Wirescanners/Laserwires, Profile Monitors  Bunch length measurements (Marc Ross proposals): Band pass mirco wave detectors Beam phasing Energy / time correclations  Common instrumentation requirements with e + International Linear Collider at Stanford Linear Accelerator Center

Layout and Length Estimates ComponentDistance [m] Pre-Gun Systems (Laser, OTR, Local Injector Controls) ~ 50 Guns and Load-Lock Installation~ 5 Y extension lines (with diagnostics and solenoidal field)~ 3 SHB 1 (solenoidal field)~ 3 SHB 2 (solenoidal field)~ 3 Buncher~ 2.5 Pre-accelerator (to 500 MeV, 17.8 MV/m)~ 30 RT – SC beamline~ 12 Injector Linac (to 5 GeV; m SC modules 20 MV/m)~ 306 e - injector to DR transfer line with SPIN rotator~25 Total Length of Injector Area439 International Linear Collider at Stanford Linear Accelerator Center

Components (e - and e + source) ComponentsCount Laser systems2 Guns2 ‘Y’ bend magnet1 Solenoidal focusing magnets9 m DipolsDiagnostic arm1 DR transfer1 DoubletsInjection LINAC2 TripletsBetween NC pre-accelerator sections1 Between NC and SC2 Total3 Klystrons (10MW)Buncher1 Pre-accelerator1 Injection LINAC6 Total8 CryomodulesPre-accelerator2 Injection LINAC17 Total19 SPIN RotatorDR In/out2 International Linear Collider at Stanford Linear Accelerator Center