A Capture Section Design for the CLIC Positron Source

A. VIVOLI*

Thanks to:

L. RINOLFI (CERN)

R. CHEHAB (IPNL & LAL / IN2P3-CNRS)

O. DADOUN, P. LEPERCQ, A. VARIOLA (LAL / IN2P3-CNRS)

V. STRAKHOVENKO (BINP)

* E-mail : Alessandro.Vivoli@cern.ch

21/04/23A. Vivoli, CLIC Positron Source,

POSIPOL 2009, LYON2

CONTENTS

• General scheme of the CLIC positron source

• Design and Simulation of the elements

• Future steps

e- gun

LaserDC gunPolarized e-

Pre-injector Linac for e-

200 MeV

e-/Target

Pre-injector Linac for e+

200 MeV

Primary beam Linac for e-

5 GeV

Inje

ctor

Lin

ac

2.66

GeV

e+ DR

e+ PDRB

oost

er L

inac

5.

14 G

eV

4 GHz

e+ BC1 e- BC1

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

2 GHz

e- DR

e- PDR

2 GHz 2 GHz 2 GHz

4 GHz 4 GHz

12 GHz 12 GHz

8 GeV48 km

2.86 GeV 2.86 GeV

e

Target

AMD

2.86 GeV 2.86 GeV

3 TeV

Base line configuration

CLIC Main Beam Injector Complex (2009)

IP

Unpolarized e+

3

4

POSITRON SOURCES USING CHANNELING FOR ILC & CLIC

• PROPOSED POSITRON TARGET FOR CLIC

e-

Crystal Amorphous

e+, e-, e-

e+

2 m

(5 GeV)

W: 1.4 mm thick W: 10 mm thick

N. simulated e- : 6000 r=2.5 mm

21/04/23 A. Vivoli, CLIC Positron Source, POSIPOL 2009, LYON

Gamma Production

21/04/23 A. Vivoli, CLIC Positron Source, POSIPOL 2009, LYON

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CHANNELING COMPTON

COMPTON: N = 75177 N / Ne- = 0.75 E = 27.7 MeV Ee- = 1.8 GeV

CHANNELING: N = 119813 N/Ne- = 19.97 E = 160.2 MeV Ee- = 5.0 GeV

By T. OMORIBy V. Strakhovenko

Positron Production

21/04/23 A. Vivoli, CLIC Positron Source, POSIPOL 2009, LYON

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N. e+ Yield e+/e-

x (rms)

mm mrad

y (rms)

mm mrad

<E> MeV

E

MeV

z (rms)* mm

49750 8.29 98075 118943 50 103 0.300*

Positron Beam Parameters at the target

By O. DADOUN

21/04/23 A. Vivoli, CLIC Positron Source, POSIPOL 2009, LYON

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Adiabatic Matching Device

• Length: L = 20 - 50 cm• Magnetic field at the

target : B0 = 6 T

• Magnetic field at the end : B(L) = 0.5 T

• Magnetic Field Behaviour :

zz

1

B)B(

0

AMD RESULTS

21/04/23 A. Vivoli, CLIC Positron Source, POSIPOL 2009, LYON

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AMD

cm

N*. e+

Yield

e+/e-

x

mm mrad

y

mm mrad

<E> MeV

E

MeV

z *

mm

z

cm MeV

50 11695 1.95 502 508 70.6 176.6 10.0* 170.8

20 16488 2.75 679 684 79.0 164.7 8.7* 136.0

CAVITY 100 KW CW (P. Lepercq)

21/04/23 A. Vivoli, CLIC Positron Source, POSIPOL 2009, LYON

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L= 58.9689 cm Fr = 1.9991552 GHz Iris : r = 20mm Ezmax(r=0)= 5.2 MV/m

21/04/23 A. Vivoli, CLIC Positron Source, POSIPOL 2009, LYON

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CAVITY 100 KW CW (P. Lepercq)

Capture Section Design

21/04/23 A. Vivoli, CLIC Positron Source, POSIPOL 2009, LYON

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e+ (200 MeV)

Target

AMD

e-

63 Cavities

Solenoid

AMD

• Length : L = 20 cm• Magnetic Filed: B = 6 - 0.5 T• Final Aperture: r = 2 cm

SOLENOID

• Length : L = 41 m• Magnetic Filed: B = 0.5 T• Drift Tube Aperture: r = 2 cm

Accelerating cavities:

• Number of cavities: N = 63• Length: L = 60 cm• Max Energy Gain: E = 5.95 MeV• Maximum Gradient: Ez (r=0) = 25 MV/m• Frequency: = 2 GHz

Capture Results

21/04/23 A. Vivoli, CLIC Positron Source, POSIPOL 2009, LYON

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S

cm

N. e+

Yield

e+/e-

x

mm mrad

y

mm mrad

<E> MeV

E

MeV

z

mm

z

cm MeV

4200 5780 0.96 6704 6681 210.9 44.97 9.9 43.6

To be optimized…

Phase spaces for the Injector Linac @ 2.4 GeV

TransverseLongitudinal

Bunch length (rms) = 5 mm

Energy spread (rms) = 65 MeV

21/04/23 13A. Vivoli, CLIC Positron Source, POSIPOL 2009, LYON

By A. LATINA

Phase spaces for the Injector Linac @ 2.4 GeV

Longitudinal distribution For acceptanceE/E = 2 % FW

Capture = 74 % of e+

rms bunch length 3.2 mm

E mean = 2.4 GeVNe+ = 6.4 x 109 / bunchE = 17 MV/mTotal distribution:E = 1.5 %

rms bunch length 5 mm

21/04/23 14A. Vivoli, CLIC Positron Source, POSIPOL 2009, LYON

By A. LATINA

21/04/23 A. Vivoli, CLIC Positron Source, POSIPOL 2009, LYON

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Capture Section (+ Bunch Compressor)

Crystal To the accelerator

Target

Adiabatic MatchingDevice Pre-accelerator

Chicane

e-

e+

Solenoid Cavities

BendingMagnets

Drift

Magnetic field

Electric field

e+

e-

e-

Magnet LINAC 2 GHz

21/04/23 A. Vivoli, CLIC Positron Source, POSIPOL 2009, LYON

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e+

Magnetic Chicane

Quadrupoles

Bunch Compressor Design

Cavities

21/04/23 A. Vivoli, CLIC Positron Source, POSIPOL 2009, LYON

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Bunch Compressor Elements

Quadrupoles:

• Number: N = 20• Length: L = 30 cm• Gradient: G = 0.5 – 5 T/m• Aperture: r = 5 cm

Accelerating cavities:

• Number of cavities: N = 63• Length: L = 60 cm• Max Energy Gain: E = 5.95 MeV• Maximum Gradient: Ez (r=0) = 25 MV/m• Frequency: = 2 GHz

Bending Magnets:

• Number: N = 4• Length: L = 30 cm• Magnetic Field: B = 0.4985 T

Drift Tubes:

• Number: N = 28• Aperture: r = 5 cm• Length: L = 10 - 30 cm

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MAGNETIC CHICANE

BS1 BS2 BS3 BS4

E1=0 E2= E1= - E2= 0 E1=0 E2= - E1= E2=0

139

mm

fo

r =

66

mra

d

e+

0.30 m 0.30 m 0.30 m0.30 m

0.29 m 0.29 m0.30 m

- -

21/04/23 A. Vivoli, CLIC Positron Source, POSIPOL 2009, LYON

By M. Martini

Chicane Modeling:

• Bending angle: = 13.17 deg• Drift: = 30 cm• Diaphragm: r = 3.5 cm

Bunch Compressor Results

21/04/23 A. Vivoli, CLIC Positron Source, POSIPOL 2009, LYON

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S

cm

N. e+

Yield

e+/e-

x

mm mrad

y

mm mrad

<E> MeV

E

MeV

z

mm

z

cm MeV

5597 5395 0.90 7831 7276 203.6 15.2 7.4 11.2

Future Steps

• Complete the positron source design&simulation up to the pre-damping ring.

• Optimize the parameters for non-polarized positrons.

• Study parameter changes for polarized positrons.

• Employ different codes for simulations (PARMELA, PLACET, GEANT4,…).

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THANKS.

The EndThe End