CLIC Drive Beam Injector Bunching System Sh Sanaye

CLIC Drive Beam Injector Bunching System Sh. Sanaye H. 1, 2, S. Doebert 2, S. H. Shaker 1, 2 1. Institute For Research in Fundamental Science (IPM), Tehran, Iran 2. CERN, Geneva, Switzerland

Contents 1. Introduction 2. Sub-harmonic bunching system 3. Travelling wave tapered buncher 4. Comparison with previous model

1. Introduction 1. 1 CLIC Drive Beam time structure Ø Main pulse consists of 24 bunch trains of 244 ns length. Ø Each of bunch trains consist of 2922 bunches with a time separation corresponds to 12 GHz. 1

1. Introduction 1. 2 Phase coding 2 ∆Ф 0=180 o ØOnly every second bucket is occupied. ØAbout 5% of particles captured in wrong buckets, called satellite bunches.

1. Introduction 1. 3 Drive Beam Complex 3 I = 24× 4. 2 A=100. 8 A f = 24× 0. 5 GHz=12 GHz

2. Sub-harmonic bunching system 4 2. Sub-harmonic bunching system 2. 1 General layout of bunching system 2. 2 Thin lens approximation Ø To maximize the population of the particles in the acceptance of the buncher. Ø To minimize the population of satellite bunches.

2. Sub-harmonic bunching system 5 2. 3 Velocity modulation bunching Before SHB Just after At point PSHB Phase Space PAR ME Phase Spectrum LA

2. Sub-harmonic bunching system 6 2. 4 Optimization of the thin lens system In drift section: In SHB(thin lens):

2. Sub-harmonic bunching system 7 2. 4 Optimization of the thin lens system Satellite population = 4. 4% 120 o SHB 3 SHB 1 Before After At point SHB 2 SHB 1 SHB 2 P 93. 1% Phase Space Phase Spectrum

2. Sub-harmonic bunching system 2. 5 The space charge effect Ø The effect of the space charge forces is investigated in various configuration of the system. 8

2. Sub-harmonic bunching system 9 2. 5 The space charge effect Ignoring the space charge With the space charge

2. Sub-harmonic bunching system 10 2. 5 The space charge effect ØThe phase space at the entrance of buncher Satellite population = 4. 4% Satellite population = 4. 7% 120 o 93. 1% 92. 6% Ignoring the space charge With the space charge

2. Sub-harmonic bunching system 11 2. 6 Travelling wave SHBs Thin lens SHB Travelling Wave SHB

2. Sub-harmonic bunching system 12 2. 6 Travelling wave SHBs Satellite population = 4. 7% Satellite population = 4. 2% 120 o 92. 6% 93. 3% Thin lens SHB Travelling Wave SHB

3. Travelling wave tapered buncher 3. 1 Longitudinal dynamics in TW buncher 13

3. Travelling wave tapered buncher 14 3. Travelling wave tapered buncher Satellite population = 3. 8% ± 11. 5 o ± 1 Me. V 3. 2 Optimization result 90. 3%

4. Comparison with previous model 15 4. Comparison with previous model Satellite population = 4. 9% n i k r o W Previous model Satellite population = 3. 8% s s e gr o r p Current model

Tanks for your attention