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) *

17/04/2015 A. Vivoli, CLIC Positron Source, POSIPOL 2009, LYON 2 CONTENTS General scheme of the CLIC positron source Design and Simulation of the elements Future steps

e - gun Laser DC gun Polarized e - Pre-injector Linac for e MeV e - /  Target Pre-injector Linac for e MeV Primary beam Linac for e - 5 GeV Injector Linac 2.66 GeV e + DR e + PDR Booster Linac 5.14 GeV 4 GHz e + BC1 e - BC1 e + BC2 e - BC2 e + Main Linac e - Main Linac 2 GHz e - DR e - PDR 2 GHz 4 GHz 12 GHz 8 GeV 48 km 2.86 GeV  e  Target AM D 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-e- Crystal Amorphous e +, e -,   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 17/04/2015A. Vivoli, CLIC Positron Source, POSIPOL 2009, LYON

Gamma Production 17/04/2015A. Vivoli, CLIC Positron Source, POSIPOL 2009, LYON 5 CHANNELINGCOMPTON COMPTON:N  = N  / Ne - = 0.75 E  = 27.7 MeV Ee - = 1.8 GeV CHANNELING: N  = N  /Ne - = E  = MeV Ee - = 5.0 GeV By T. OMORIBy V. Strakhovenko

Positron Production 17/04/2015A. Vivoli, CLIC Positron Source, POSIPOL 2009, LYON 6 N. e + Yield e + /e -  x (rms)  mm mrad  y (rms)  mm mrad MeV  E MeV  z (rms)* mm * Positron Beam Parameters at the target By O. DADOUN

17/04/2015A. Vivoli, CLIC Positron Source, POSIPOL 2009, LYON 7 Adiabatic Matching Device Length: L = cm Magnetic field at the target : B 0 = 6 T Magnetic field at the end : B(L) = 0.5 T Magnetic Field Behaviour :

AMD RESULTS 17/04/2015A. Vivoli, CLIC Positron Source, POSIPOL 2009, LYON 8 AMD cm N*. e + Yield e + /e -  x  mm mrad  y  mm mrad MeV  E MeV  z * mm  z  cm MeV * *136.0

CAVITY 100 KW CW (P. Lepercq) 17/04/2015A. Vivoli, CLIC Positron Source, POSIPOL 2009, LYON 9 L= cm Fr = GHz Iris : r = 20mm Ez max (r=0)= 5.2 MV/m

17/04/2015A. Vivoli, CLIC Positron Source, POSIPOL 2009, LYON 10 CAVITY 100 KW CW (P. Lepercq)

Capture Section Design 17/04/2015A. Vivoli, CLIC Positron Source, POSIPOL 2009, LYON 11 e + (200 MeV) Target  AMD e-e- 63 Cavities  Solenoid AMD Length :L = 20 cm Magnetic Filed:B = 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:E z (r=0) = 25 MV/m Frequency: = 2 GHz

Capture Results 17/04/2015A. Vivoli, CLIC Positron Source, POSIPOL 2009, LYON 12 S cm N. e + Yield e + /e -  x  mm mrad  y  mm mrad MeV  E MeV  z mm  z  cm MeV To be optimized…

Phase spaces for the Injector 2.4 GeV Transverse Longitudinal Bunch length (rms) = 5 mm Energy spread (rms) = 65 MeV 17/04/201513A. Vivoli, CLIC Positron Source, POSIPOL 2009, LYON By A. LATINA

Phase spaces for the Injector 2.4 GeV Longitudinal distribution For acceptance  E/E = 2 % FW Capture = 74 % of e + rms bunch length 3.2 mm E mean = 2.4 GeV N e+ = 6.4 x 10 9 / bunch  E = 17 MV/m Total distribution:  E = 1.5 % rms bunch length 5 mm 17/04/201514A. Vivoli, CLIC Positron Source, POSIPOL 2009, LYON By A. LATINA

17/04/2015A. Vivoli, CLIC Positron Source, POSIPOL 2009, LYON 15 Capture Section (+ Bunch Compressor) CrystalTo the accelerator Target  Adiabatic Matching Device Pre-accelerator Chicane e-e- e+e+ SolenoidCavities  Bending Magnets Drift Magnetic field Electric field e+e+ e-e- e-e- Magnet LINAC 2 GHz

17/04/2015A. Vivoli, CLIC Positron Source, POSIPOL 2009, LYON 16 e+e+ Magnetic Chicane Quadrupoles Bunch Compressor Design Cavities

17/04/2015A. Vivoli, CLIC Positron Source, POSIPOL 2009, LYON 17 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:E z (r=0) = 25 MV/m Frequency: = 2 GHz Bending Magnets: Number:N = 4 Length:L = 30 cm Magnetic Field:B = T Drift Tubes: Number:N = 28 Aperture:r = 5 cm Length:L = cm

18 MAGNETIC CHICANE BS1BS2BS3BS4  E1=0 E2=  E1= -  E2= 0 E1=0 E2= -  E1=  E2=0 139 mm for =66 mrad e+e m 0.29 m 0.30 m  -- -- 17/04/2015A. Vivoli, CLIC Positron Source, POSIPOL 2009, LYON By M. Martini Chicane Modeling: Bending angle:  = deg Drift: = 30 cm Diaphragm:r = 3.5 cm

Bunch Compressor Results 17/04/2015A. Vivoli, CLIC Positron Source, POSIPOL 2009, LYON 19 S cm N. e + Yield e + /e -  x  mm mrad  y  mm mrad MeV  E MeV  z mm  z  cm MeV

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,…). 17/04/2015A. Vivoli, CLIC Positron Source, POSIPOL 2009, LYON 20

17/04/2015A. Vivoli, CLIC Positron Source, POSIPOL 2009, LYON 21 THANKS. The End