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Electron Source Configuration - KEK

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					  International Linear Collider
  at Stanford Linear Accelerator Center




Electron Source Configuration

                              Axel Brachmann
                                 - SLAC -

                    Jan. 19 2006, KEK GDE meeting
 International Linear Collider
 at Stanford Linear Accelerator Center




Layout as defined in the Baseline Configuration Document
                                                 E=70-100 MeV
               laser          Positron-style room-
                                 temperature                        standard ILC
                              accelerating section                 SCRF modules




              sub-harmonic                           diagnostics
           bunchers + solenoids                        section




         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-2001-20
                      International Linear Collider
                      at Stanford Linear Accelerator Center



                          120 kV DC Gun – Baseline Design is SLC Gun
                                       Ion Pump                                 RGA




                                Load-lock and
                                   cesiator
                                on other side


                                                                                        BPM
       High voltage
         insulator




                                                                                          laser beam
                                                                                              e- beam




Load-lock chamber
  connects here
                                                                                      Magnetic lens




                                                  Approximate location   Leak valve
                                                      of cathode
 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 :
        Cavity #     F [MHz]      Voltage [kV]   Rs [M]     Q0         P [W]
           1        108 (1/12)          40         8.8     3.4*104      220
           2         433 (1/3)          44         4.4     1.7*104      360


   •   Distance between sub-harmonic buncher cavities: 200 cm
   •   Bunch compression: 97o rms at entrance to second SHB cavity, and 30o 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
       International Linear Collider
       at Stanford Linear Accelerator Center




                                NC Pre-Accelerator


• Energy from 12 MeV  ~ 70 - 100 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: Eacc = 17.8 MV/m
   •   Lower energy requires doublets instead of triplets


 STEP 2

   • Energy gain to 5 GeV by 18 standard cryomodules
   • Gradient: Eacc = 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
Component                                                   Distance [m]

Pre-Gun Systems                                                 ~ 50
(Laser, OTR, Local Injector Controls)
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; 18 17 m SC modules 20 MV/m)          ~ 306

e- injector to DR transfer line with SPIN rotator               ~25

Total Length of Injector Area                                   439
           International Linear Collider
           at Stanford Linear Accelerator Center



                              Components (e- and e+ source)
Components                                                    Count

Laser systems                                                  2
Guns                                                           2
‘Y’ bend magnet                                                1
Solenoidal focusing magnets                                   9m
Dipols              Diagnostic arm                             1
                    DR transfer                                1
Doublets            Injection LINAC                            2
Triplets            Between NC pre-accelerator sections        1
                    Between NC and SC                          2
                    Total                                      3
Klystrons (10MW)    Buncher                                    1
                    Pre-accelerator                            1
                    Injection LINAC                            6
                    Total                                      8
Cryomodules         Pre-accelerator                            2
                    Injection LINAC                            17
                    Total                                      19
SPIN Rotator        DR In/out                                  2

				
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posted:3/4/2013
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