1

Tessa CharlesAustralian Synchrotron / Monash University

Bunch Compression Schemes for X-band FELs

2

AXXS (Australian X-band X-ray Source)

• Upgrade the storage ring with an MBA lattice with e < 1 nm rad, in the existing tunnel with the same source points.

• Build a 3 GeV x-band linac to inject a low emittance beam into the storage ring.

• Use a second x-band linac to generate a 6 GeV beam for an XFEL.

CLIC Workshop 2015 – Tessa Charles - 2

• Comparison of bunch compression schemes– Magnetic Chicane (most FELs)– Double Achromat (e.g. MAX IV)– Harmonic Linearization – Optical Linearization

Today’s talk• Why these schemes• Preliminary simulation results

Bunch compressors we’re considering

CLIC Workshop 2015 – Tessa Charles - 3

Magnetic Chicane

R56 <0, T566 >0

δE

z

Chirped, linearized beam

Compressed beam

CLIC Workshop 2015 – Tessa Charles - 4

AXXS (Australian X-band X-ray Source) - Two Designs

1. Base line design: S-band with X-band structure for linearizing before BC1

2. Alternative design being considered: X-band the whole way

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

S-band~40 MV/m6 x 4 m

X-band~65 MV/m4 x 0.75 m

X-band~65 MV/m90 x 0.75 m

~150 m

GunInjector

BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

X-band~65 MV/m10 x 0.75 m

X-band~65 MV/m4 x 0.75 m

X-band~65 MV/m90 x 0.75 m

~110 m

BC1

CLIC Workshop 2015 – Tessa Charles - 5

AXXS (Australian X-band X-ray Source)

CLIC Workshop 2015 – Tessa Charles - 6

How to linearize the longitudinal phase space?

Harmonic vs Optical

linearization

CLIC Workshop 2015 – Tessa Charles - 7

All X-band design

• One way to linearize the longitudinal phase - Optical linearization

CLIC Workshop 2015 – Tessa Charles - 8

Optical Linearization - Theoretical description

Optimal compression =>

When higher order terms are considered…

Bunch length after compression (to 1st order):

Y. Sun et al. Phys. Rev. ST Accel. Beams 17, 110703 (2014)

CLIC Workshop 2015 – Tessa Charles - 9

Optical Linearization - Choosing R56, T566 & U5666

CLIC Workshop 2015 – Tessa Charles - 10

Optical Linearization

Linac1 end /BC1 entrance

BC1 end

Linac2 end /BC2 entrance

BC2 end

Y. Sun et al. Phys. Rev. ST Accel. Beams 17, 110703 (2014)

CLIC Workshop 2015 – Tessa Charles - 11

Optical Linearization

Y. Sun et al. Phys. Rev. ST Accel. Beams 17, 110703 (2014)

T566 = 80 mm R56 = 17 mm

CLIC Workshop 2015 – Tessa Charles - 12

Positive R56 & positive T566 Self Linearizing

BC1: R56 = 3.23 cm T566 = 9.26 cm

BC2: R56 = 2.6 c m T566 = -17.8 cm

MAX IV

Detailed Design Report on the MAX IV Facility (2010)

CLIC Workshop 2015 – Tessa Charles - 13

Preliminary Simulation Results

Four simulations of linac compression schemes compared.

A work in progress

CLIC Workshop 2015 – Tessa Charles - 14

01 – BASE LINE DESIGNInc. 12 GHz linearizer

CLIC Workshop 2015 – Tessa Charles - 15

S band with X band structure for linearizing before BC1

Base line design (S-band w X-band linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

S-band~40 MV/m

X-band~65 MV/m

X-band~65 MV/m

X-band12 GHz

Initial beam parameters:

• mec (pCentral) = 257.65• Q = 2.5x10-10 C• Bunch length (rms) = 2.64 ps

Simulations based of Andrea Latina’s elegant files.

CLIC Workshop 2015 – Tessa Charles - 16

S band with X band structure for linearizing before BC1

Base line design (S-band w X-band linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

S-band~40 MV/m

X-band~65 MV/m

X-band~65 MV/m

X-band12 GHz

CLIC Workshop 2015 – Tessa Charles – 17

S band with X band structure for linearizing before BC1

Base line design (S-band w X-band linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

S-band~40 MV/m

X-band~65 MV/m

X-band~65 MV/m

X-band12 GHz

CLIC Workshop 2015 – Tessa Charles - 18

S band with X band structure for linearizing before BC1

Base line design (S-band w X-band linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

S-band~40 MV/m

X-band~65 MV/m

X-band~65 MV/m

X-band12 GHz

CLIC Workshop 2015 – Tessa Charles - 19

S band with X band structure for linearizing before BC1

Base line design (S-band w X-band linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

S-band~40 MV/m

X-band~65 MV/m

X-band~65 MV/m

X-band12 GHz

CLIC Workshop 2015 – Tessa Charles - 20

S band with X band structure for linearizing before BC1

Base line design (S-band w X-band linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

S-band~40 MV/m

X-band~65 MV/m

X-band~65 MV/m

X-band12 GHz

CLIC Workshop 2015 – Tessa Charles - 21

S band with X band structure for linearizing before BC1

Base line design (S-band w X-band linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

S-band~40 MV/m

X-band~65 MV/m

X-band~65 MV/m

X-band12 GHz

Compression Ratio after BC1: 8.34

CLIC Workshop 2015 – Tessa Charles - 22

S band with X band structure for linearizing before BC1

Base line design (S-band w X-band linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

S-band~40 MV/m

X-band~65 MV/m

X-band~65 MV/m

X-band12 GHz

CLIC Workshop 2015 – Tessa Charles - 23

S band with X band structure for linearizing before BC1

Base line design (S-band w X-band linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

S-band~40 MV/m

X-band~65 MV/m

X-band~65 MV/m

X-band12 GHz

CLIC Workshop 2015 – Tessa Charles - 24

Base line design (S-band w X-band linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

S-band~40 MV/m

X-band~65 MV/m

X-band~65 MV/m

X-band12 GHz

CLIC Workshop 2015 – Tessa Charles - 25

Base line design (S-band w X-band linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

S-band~40 MV/m

X-band~65 MV/m

X-band~65 MV/m

X-band12 GHz

CLIC Workshop 2015 – Tessa Charles - 26

Base line design (S-band w X-band linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

S-band~40 MV/m

X-band~65 MV/m

X-band~65 MV/m

X-band12 GHz

CLIC Workshop 2015 – Tessa Charles - 27

S band with X band structure for linearizing before BC1

Base line design (S-band w X-band linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

S-band~40 MV/m

X-band~65 MV/m

X-band~65 MV/m

X-band12 GHz

CLIC Workshop 2015 – Tessa Charles - 28

Base line design (S-band w X-band linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

S-band~40 MV/m

X-band~65 MV/m

X-band~65 MV/m

X-band12 GHz

End of linac: Compression Ratio: 100.80

CLIC Workshop 2015 – Tessa Charles - 29

Base line design (S-band w X-band linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

S-band~40 MV/m

X-band~65 MV/m

X-band~65 MV/m

X-band12 GHz

CLIC Workshop 2015 – Tessa Charles - 30

Base line design (S-band w X-band linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

S-band~40 MV/m

X-band~65 MV/m

X-band~65 MV/m

X-band12 GHz

CLIC Workshop 2015 – Tessa Charles - 31

02 – ALL X-BAND Without a harmonic linearizer

CLIC Workshop 2015 – Tessa Charles - 32

CLIC Workshop 2015 – Tessa Charles - 33

02 All X-band (w/o harmonic linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

X-band~65 MV/m

X-band~65 MV/m

X-band~65 MV/m

02 All X-band (w/o harmonic linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

X-band~65 MV/m

X-band~65 MV/m

X-band~65 MV/m

CLIC Workshop 2015 – Tessa Charles - 34

02 All X-band (w/o harmonic linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

X-band~65 MV/m

X-band~65 MV/m

X-band~65 MV/m

CLIC Workshop 2015 – Tessa Charles - 35

02 All X-band (w/o harmonic linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

X-band~65 MV/m

X-band~65 MV/m

X-band~65 MV/m

CLIC Workshop 2015 – Tessa Charles - 36

02 All X-band (w/o harmonic linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

X-band~65 MV/m

X-band~65 MV/m

X-band~65 MV/m

CLIC Workshop 2015 – Tessa Charles - 37

02 All X-band (w/o harmonic linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

X-band~65 MV/m

X-band~65 MV/m

X-band~65 MV/m

CLIC Workshop 2015 – Tessa Charles - 38

Compression Ratio after BC1: 9.35

02 All X-band (w/o harmonic linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

X-band~65 MV/m

X-band~65 MV/m

X-band~65 MV/m

CLIC Workshop 2015 – Tessa Charles - 39

02 All X-band (w/o harmonic linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

X-band~65 MV/m

X-band~65 MV/m

X-band~65 MV/m

CLIC Workshop 2015 – Tessa Charles - 40

02 All X-band (w/o harmonic linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

X-band~65 MV/m

X-band~65 MV/m

X-band~65 MV/m

CLIC Workshop 2015 – Tessa Charles - 41

02 All X-band (w/o harmonic linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

X-band~65 MV/m

X-band~65 MV/m

X-band~65 MV/m

CLIC Workshop 2015 – Tessa Charles - 42

02 All X-band (w/o harmonic linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

X-band~65 MV/m

X-band~65 MV/m

X-band~65 MV/m

CLIC Workshop 2015 – Tessa Charles - 43

02 All X-band (w/o harmonic linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

X-band~65 MV/m

X-band~65 MV/m

X-band~65 MV/m

CLIC Workshop 2015 – Tessa Charles - 44

02 All X-band (w/o harmonic linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

X-band~65 MV/m

X-band~65 MV/m

X-band~65 MV/m

CLIC Workshop 2015 – Tessa Charles - 45

End of linac: Compression Ratio: 93.52

02 All X-band (w/o harmonic linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

X-band~65 MV/m

X-band~65 MV/m

X-band~65 MV/m

CLIC Workshop 2015 – Tessa Charles - 46

02 All X-band (w/o harmonic linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

X-band~65 MV/m

X-band~65 MV/m

X-band~65 MV/m

CLIC Workshop 2015 – Tessa Charles - 47

Optics not yet optimized

Compression Ratio: 93.52

02 All X-band (w/o harmonic linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

X-band~65 MV/m

X-band~65 MV/m

X-band~65 MV/m

CLIC Workshop 2015 – Tessa Charles - 48

03 – ALL X-BAND Inc. 24 GHz linearizer

CLIC Workshop 2015 – Tessa Charles - 49

03 All X-band (24GHz linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

X-band12 GHz

X-band~65 MV/m

X-band~65 MV/m

X-band24 GHz

CLIC Workshop 2015 – Tessa Charles - 50

03 All X-band (24GHz linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

X-band12 GHz

X-band~65 MV/m

X-band~65 MV/m

X-band24 GHz

CLIC Workshop 2015 – Tessa Charles - 51

03 All X-band (24GHz linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

X-band12 GHz

X-band~65 MV/m

X-band~65 MV/m

X-band24 GHz

CLIC Workshop 2015 – Tessa Charles - 52

03 All X-band (24GHz linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

X-band12 GHz

X-band~65 MV/m

X-band~65 MV/m

X-band24 GHz

CLIC Workshop 2015 – Tessa Charles - 53

03 All X-band (24GHz linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

X-band12 GHz

X-band~65 MV/m

X-band~65 MV/m

X-band24 GHz

CLIC Workshop 2015 – Tessa Charles - 54

CLIC Workshop 2015 – Tessa Charles - 55

Compression Ratio after BC1: 10.19

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

X-band12 GHz

X-band~65 MV/m

X-band~65 MV/m

X-band24 GHz

03 All X-band (24GHz linearizer)

03 All X-band (24GHz linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

X-band12 GHz

X-band~65 MV/m

X-band~65 MV/m

X-band24 GHz

CLIC Workshop 2015 – Tessa Charles - 56

03 All X-band (24GHz linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

X-band12 GHz

X-band~65 MV/m

X-band~65 MV/m

X-band24 GHz

CLIC Workshop 2015 – Tessa Charles - 57

03 All X-band (24GHz linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

X-band12 GHz

X-band~65 MV/m

X-band~65 MV/m

X-band24 GHz

CLIC Workshop 2015 – Tessa Charles - 58

03 All X-band (24GHz linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

X-band12 GHz

X-band~65 MV/m

X-band~65 MV/m

X-band24 GHz

CLIC Workshop 2015 – Tessa Charles - 59

03 All X-band (24GHz linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

X-band12 GHz

X-band~65 MV/m

X-band~65 MV/m

X-band24 GHz

CLIC Workshop 2015 – Tessa Charles - 60

03 All X-band (24GHz linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

X-band12 GHz

X-band~65 MV/m

X-band~65 MV/m

X-band24 GHz

CLIC Workshop 2015 – Tessa Charles - 61

03 All X-band (24GHz linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

X-band12 GHz

X-band~65 MV/m

X-band~65 MV/m

X-band24 GHz

End of linac:

Compression Ratio: 103.86

CLIC Workshop 2015 – Tessa Charles - 62

03 All X-band (24GHz linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

X-band12 GHz

X-band~65 MV/m

X-band~65 MV/m

X-band24 GHz

Along the length of the linac

CLIC Workshop 2015 – Tessa Charles - 63

04 – ALL X-BAND Inc. 36 GHz linearizer

CLIC Workshop 2015 – Tessa Charles - 64

04 All X-band (36 GHz linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

X-band12 GHz

X-band~65 MV/m

X-band~65 MV/m

X-band36 GHz

CLIC Workshop 2015 – Tessa Charles - 65

04 All X-band (36 GHz linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

X-band12 GHz

X-band~65 MV/m

X-band~65 MV/m

X-band36 GHz

CLIC Workshop 2015 – Tessa Charles - 66

04 All X-band (36 GHz linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

X-band12 GHz

X-band~65 MV/m

X-band~65 MV/m

X-band36 GHz

CLIC Workshop 2015 – Tessa Charles - 67

04 All X-band (36 GHz linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

X-band12 GHz

X-band~65 MV/m

X-band~65 MV/m

X-band36 GHz

CLIC Workshop 2015 – Tessa Charles - 68

04 All X-band (36 GHz linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

X-band12 GHz

X-band~65 MV/m

X-band~65 MV/m

X-band36 GHz

CLIC Workshop 2015 – Tessa Charles - 69

04 All X-band (36 GHz linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

X-band12 GHz

X-band~65 MV/m

X-band~65 MV/m

X-band36 GHz

Compression Ratio after BC1: 52.65

CLIC Workshop 2015 – Tessa Charles - 70

04 All X-band (36 GHz linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

X-band12 GHz

X-band~65 MV/m

X-band~65 MV/m

X-band36 GHz

CLIC Workshop 2015 – Tessa Charles - 71

04 All X-band (36 GHz linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

X-band12 GHz

X-band~65 MV/m

X-band~65 MV/m

X-band36 GHz

CLIC Workshop 2015 – Tessa Charles - 72

04 All X-band (36 GHz linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

X-band12 GHz

X-band~65 MV/m

X-band~65 MV/m

X-band36 GHz

CLIC Workshop 2015 – Tessa Charles - 73

04 All X-band (36 GHz linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

X-band12 GHz

X-band~65 MV/m

X-band~65 MV/m

X-band36 GHz

CLIC Workshop 2015 – Tessa Charles - 74

04 All X-band (36 GHz linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

X-band12 GHz

X-band~65 MV/m

X-band~65 MV/m

X-band36 GHz

CLIC Workshop 2015 – Tessa Charles - 75

04 All X-band (36 GHz linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

X-band12 GHz

X-band~65 MV/m

X-band~65 MV/m

X-band36 GHz

CLIC Workshop 2015 – Tessa Charles - 76

End of linac:Compression Ratio: 110.98

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

X-band12 GHz

X-band~65 MV/m

X-band~65 MV/m

X-band36 GHz

04 All X-band (36 GHz linearizer)

CLIC Workshop 2015 – Tessa Charles - 77

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

X-band12 GHz

X-band~65 MV/m

X-band~65 MV/m

X-band36 GHz

Along the length of the linac:

04 All X-band (36 GHz linearizer)

CLIC Workshop 2015 – Tessa Charles - 78

04 All X-band (36 GHz linearizer)

Gun Injector BC1 BC2Dogleg

Linac2

UndulatorLinac

1

Experimental Station

X-band12 GHz

X-band~65 MV/m

X-band~65 MV/m

X-band36 GHz

Along the length of the linac:

CLIC Workshop 2015 – Tessa Charles - 79

Comparison of the 4 simulated scenarios

End of linac comparison

CLIC Workshop 2015 – Tessa Charles - 80

01 S-band w X-band linearizer (Base line) 02 all X-band w/o linearizer

03 all X-band w 24 GHz linearizer 04 all X-band w 36 GHz linearizer

Where to from here…

• Further optimization of chicane simulations and inclusions of additional effects (CSR) & optimize optics

• Look into beam parameters optimal for photon production

• Investigate optical linearization in chicanes

• Investigate optical linearization in double achromats

CLIC Workshop 2015 – Tessa Charles - 81

Thank you