In the name of God the Beneficent the

In the name of God, the Beneficent the Merciful

Beam Dynamics Studies of the IPM Linac Shahin Sanaye Hajari, Saeed Haghtalab

Contents 1 Coupler asymmetry 1. 1 Induced kick 1. 2 Additional emittance growth 2 New buncher design 2. 1 The need for a new buncher 2. 2 Beam dynamics in a TW buncher 2. 3 New buncher 3 Solenoid Channel 3. 1 Review of the beam dynamics study results 3. 2 Final design 3. 3 Misalignment studies

Coupler asymmetry

1 Coupler asymmetry 1. 1 Induced kick 1

1 Coupler asymmetry 2 Beam cross section at the middle of the buncher Kick and emittance compensation using a dipole field ? ? ?

New buncher design

2 New buncher design 3

2 New buncher design 4 2. 2 Beam dynamics in a TW buncher Ø Longitudinal equation of motion in a TW structure: Principle wave amplitude RF phase seen by the particle Phase velocity Ø Synchronous particle & Motion of the nonsynchronous particle

2 New buncher design 2. 2 Beam dynamics in a TW buncher Ø Damped oscillatory motion Big The 5

2 New buncher design 6 2. 2 Beam dynamics in a TW buncher Ø Damped oscillatory motion Effective bunching: Beam acceleration & Field increase

2 New buncher design 2. 2 Beam dynamics in a TW buncher Ø Buncher design and optimization ü Adiabatic change of the structure 7

2 New buncher design 8 2. 2 Beam dynamics in a TW buncher Ø Buncher design and optimization ü Particle Tracking Ø Optimization criteria: ü To minimize the bunch length. ü To minimize the energy spread. ü To reach the required energy.

2 New buncher design 9 2. 2 Beam dynamics in a TW buncher Ø Buncher design and optimization ü Low initial electric field Larger phase acceptance Lower energy spread Lower emittance growth

2 New buncher design 10 2. 3 New buncher Ø Beam parameters and comparison with previous designs ü L = 40 cm (Pre-buncher included) Larger phase acceptance

2 New buncher design 2. 3 New buncher Ø Beam parameters and comparison with previous designs ü L = 50 cm (Pre-buncher included) 11

Solenoid Channel

3 Solenoid channel 12

3 Solenoid channel 13 Emittance Measurement

3 Solenoid channel 14

3 Solenoid channel 15

3 Solenoid channel 16

3 Solenoid channel Solenoid misalignments? 17

3 Solenoid channel 3. 3 Misalignment Studies Ø Focusing mechanism 18

3 Solenoid channel 3. 3 Misalignment Studies Ø Single particle trajectory 19

3 Solenoid channel 20

3 Solenoid channel 21

3 Solenoid channel 22 3. 3 Misalignment Studies Ø Offset

3 Solenoid channel 3. 3 Misalignment Studies Ø What to do? 1. Extend the strange buncher field sligthly more. Then the beam dynamics will be less sensitive to misalignments! 23

3 Solenoid channel 3. 3 Misalignment Studies Ø What to do? 2. Find the magnetic axis of the solenoid by measurement. 23

3 Solenoid channel 3. 3 Misalignment Studies Ø What to do? 2. Find the magnetic axis of the solenoid by measurement. 23

3 Solenoid channel 23 Beam position Measurement

Thanks for your attention!