Parameter L-band S-band X-band

Length (m) 5.0 4.0 1.0

Aperture 2a (mm) 48 31 9

Gradient (Unloaded/Loaded) (MV/m)

17/13 28/22 50/40

Power/structure (MW) 80 90 50

Beam Loading Compensation T/F T T

Possible Configuration (struct/klyst)

4/2 4/2 4/2

Design RDS RDS RDDS

Rough LINAC parameters

Based on NLC study

Parameter CLIC 2007 Unit

Initial Energy 0.01 GeV

Final Energy 0.2 GeV

RF Frequency 1.5 GHz

Unloaded/Loaded Gradient 21/17 MV/m

Power per structure 80 MW

Linac Length 15 m

No of Klystrons 2

Transport Efficiency80 (electrons)

%

Electron and Positron Pre-Injector-LINAC’s

S-band could be used for electrons, positron linac more challenging, solenoids over high gradient structures

Parameter CLIC 2007 Unit

Initial Energy 0.2 GeV

Final Energy 2.424 GeV

RF Frequency 1.5 / 3 GHz

Unloaded/Loaded Gradient 17/13 28/22 MV/m

Power per structure 80-90 MW

Linac Length 170 / 120 m

No of Klystrons 17 / 13

Transport Efficiency 95 %

Electron and Positron Injector-LINAC

Positrons need L-band, electrons can use S-band

Parameter CLIC 2007 Unit

Energy 2.424 GeV

Initial and Final Bunch Length

1.5/0.25 mm

Initial and Final Energy Spread

0.14/0.8 %

RF Frequency 1.5 / 3 GHz

RF Voltage 422/211 MV

Linac Length 32/ 12 m

No of Klystrons 2/1

Transport Efficiency 100 %

Bunch Compressor first Stage

Choice of Frequency, Beam stability

NLC chose L-band for tolerances

Parameter CLIC 2007 Unit

Initial Energy 2.424 GeV

Final Energy 9 GeV

RF Frequency 3 / 12 GHz

Unloaded/Loaded Gradient 28/22 / 50/40 MV/m

Power per structure ~90 MW

Linac Length 350 / 195 m

No of Klystrons ~38 /~83

Transport Efficiency 100 %

Booster LINAC

Choice of Frequency, wake fields have to be studied due to the short bunch spacing

Parameter CLIC 2007 Unit

Energy 9 GeV

Initial and Final Bunch Length

0.25/0.044 mm

Initial and Final Energy Spread

0.17/1.3-1.8 %

RF Frequency 12 GHz

RF Voltage 1500-2300 MV

Linac Length 40-70 m

No of Klystrons 20-35

Transport Efficiency 100 %

Bunch Compressor second Stage

Can we optimize the initial energy ?,

has to be very flexible therefore we need margin

CLIC injectors local

RF gunUnpolarized e-

e+ DR

e+ PDR

Booster Linac 7 GeV 3 GHz

e+ BC1 e- BC1

e+ BC2 e- BC2e+ Main Linac e- Main Linac

12 GHz, 100 MV/m, 21 km 12 GHz, 100 MV/m, 21 km

BDS 2.6 km

BDS 2.6 km

e- DR

e- PDR

Las

er

e- /e+

Tar

get

Pre

-inj

ecto

r L

inac

for

e+

2.4

GeV

Pri

mar

y be

am

Lin

ac f

or e

-

2 G

eV 1

.5 G

Hz

1.5

GH

z

2.424 GeV2.424 GeV

12 GHz 12 GHz

Laser

DC

gunP

olarized e-

Pre-injector

Linac for e

-

2.4 GeV

1.5 GH

z

Booster Linac 7 GeV

Central vs Local Injectors

Cost, Performance, Reliability, Maintainability, Operability, upgrade scenario

Cost: from NLC

Injector Total: 610 M$ (CV =120,DR=104, Material=387)

500 m S-band linac: 50 M$

Pre LINAC (old): 120 M$

~ additional cost for local injectors: 200-250 M$

Current cost estimate for 30k transfer line: 240 MCHF

Performance: long low emittance transport worrisome (current ILC subject), alternative bunch compressor scenarios

CLIC injectors local

RF gunUnpolarized e-

e+ DR

e+ PDR

Booster Linac 7 GeV

3 GHz

e+ BC2

e- BC2

e+ Main Linac

e- Main Linac

12 GHz, 100 MV/m, 21 km

12 GHz, 100 MV/m, 21 km

e- DR

e- PDR

2.424 GeV

2.424 GeV

e+ BC1

12 GHz

12 GHz

LaserDC gunPolarized e-

Pre-injector Linac for e-

2.4 GeV

3 GHz

e- BC1Booster Linac

7 GeV

Laser

e-/e+ Target

Pre-injector Linac for e+

2.4 GeV

Primary beam Linac for e-

2 GeV

1.5 GHz

Conclusions and Remarks

Challenging but not impossible (No show stoppers found) !

Frequency choices due to acceptance, tolerances, stability and cost

No detailed overhead for beam loading compensation

Beam stability and tolerances have to be studied (wake fields in linacs, NLC did not have big margin, bunch spacing)

Pre-damping design needed (we need one for electrons too)

Polarized Positrons (how and when)

Bunch compressor studies necessary for system optimization and detailed beam parameters

Long low emittance transport has to be studied in case of central complex

Keep in mind local injectors as an option

Should we have also 1.5 GHz for the Drive Beam ?

PHIN-gun could be used for testing CLIC injector issues in the future