Status of the CLIC Injectors

LCWS 2014, Belgrade, October 6th-10th, 2014 Steffen Döbert, BE-RF

No changes to the electron injector

Some work started on optimizing thepositron source with a student started recently

Continue to develop the drive beam injector front end, see LCWS 2013

Some work on the new baseline for CLIC

Positron source Plan to have for the first time consistent simulations from

the target to the damping ring and optimize the positron yield.New Student Cafer Bayar joint us very recently and started to work.

Phase space after target, after AMD and at the end of the 200 MeV pre-injector linac using CDR parameters

Positron source

Very preliminary studies, playing with acceleration and deceleration scenarios. Increasing the solenoid field to 1 T instead of 0.5 T seems to help a lot. Is it feasible, affordable ?

Cafer Bayar

CLIC DB front end,Post CDR Project

Major components under development, gun, SHB, PB, TW-BuncherAs well as power sources, up to 100 kW , wide band solid state source at 500 MHz and 20 MW L-band klystron with 70 % efficiency (two prototypes have been ordered with Thales and Toshiba)

Gun SHB 1-2-3

PB TW-Buncher Acc. Structures

500 MHz

Modulator-klystrons, 1 GHz, 20 MW

~ 140 keV ~ 12 MeV

Diagnostics

~ 3 MeV

Thermionic Gun design

New CLIC base line studies

Alternative layout: without positron driver linac and e- PDR, 2 GHz bunch spacing

everywhere

Pre-injector e- Linac

e-e-

3300 ns

156ns

156ns

e+

Positron production pulse

Save two rings, positron driver linac, and tunnel length (saving potential 200 MCHF)

Injector Linac

Booster Linac2 GHz e- DR

gun

PDR

e+ DR BC1

DC gun

target

6 GeV

2.86 GeV0.2 GeV

Layout with undulator based positron source

IP

target

BDS Main LinacMain Linac

Injector Linac

Booster Linac2 GHz

Pre-injector e- Linac

e- DRgun

e+ DR BC1

DC gun

target

6 GeV

2.86 GeV0.2 GeV

Spin rotator

to main linacs

Undulator positron source

Undulator 350 m

2.86 GeV linac ? 300m

BDS

Photons 300 m

~1000 m

to transfer line, DR

Main beam bypass line

from injectors

PDR

Minimum scenario for upgrade to positron polarization and fully compatible with conventional layout

Undulator based positron source

Consequences:

400 -1000 m more linac length (both sides ?)

Separate injector linac for positrons 2.86 GeV

transfer line from the tunnel to the injector

complex

Spin rotator before and after damping ring

(needed anyway for any polarized scheme)

Gap in damping ring due the delayed beams

Main beam bypass around positron

production

Coupling of the two beams

How about a dedicated scheme ?

IPBDS Main LinacMain Linac

Booster Linac6 GeV

e- DR

DC gun

2.86 GeV

BDS

PDR

e+ DR

DR and injector at the end of each side

Conclusion

For time being minimum effort going into the main beam injector studies due to lack of manpower and other priorities in the projectWe feel it is not the most critical area for CLIC to work on

Some effort in developing the drive beam injector front end including the sophisticated power sources.Wide band for sub-harmonic switching and very high efficiency for drive beam

Hopefully we can revive some work on the positron source with the new student

No conclusions yet for the new baseline