Sergey Antipov, University of Chicago Fermilab Mentor: Sergei Nagaitsev Injection to IOTA ring

Integrable Optics Test Accelerator Proof-of-principle experiment designed to demonstrate a concept of integrable accelerator lattice with highly non-linear optics. Demonstrate that huge nonlinear tune shifts can be achieved in a realistic accelerator design My part: Design injection part of the ring and conduct first-stage experiments with non-linear optics

ASTA linac ParameterValue Energy150 MeV Number of e in bunch 10 9 Circumference40 m Bending dipole field0.7 T RF voltage50 kV Max β x, β y 9 m, 4 m Min β x, β y 0.1 m, 0.25 m Momentum compaction0.14 Betatron tune Q x,Q y = 3.2 (2.4 to 3.6) Equilibrium transverse emittance 0.06 μ m (non-normalized) Synchrotron damping time~ 1 s

Energy150 MeV Emittance, normalized 5 μ m β -functions ~ 100 cm RMS beam size~ 0.2 mm Physical aperture50 mm Bend angle15 deg Lattice functions RMS beam size Injection section Optics designed by Gene Kafka

Optics is flexible Optics designed by Gene Kafka Integrable Optics Optical Stochastic Cooling

Summary of requirements Single turn injection (No storage needed) Should suit both integrable optics and optical stochastic cooling lattice designs Injection kicker should be able to work for experiments Proton injection? Components: Beam transmission line Septum magnet Fast kicker Local orbit bump (if any) Injection procedure. Orbit bump is not shown

Single turn injection Kick:

Plan Choose a design of injection magnet Determines separation of orbits Locations of magnet and kicker Beta-functions Kick angle Design of kicker Voltage Transmission line Should provide matching ( β, α, D, D` )

Septum magnet Place particles onto the correct trajectory Bend ~ 15 deg. Installed in high-beta region to reduce the kick Options: Can be DC (heating might be an issue) or pulsed (stability might be an issue) Current sheet isolation or Lambertson

Septum design Current sheet isolationLambertson

DC Lambertson septum ParameterValue Bend angle15 deg Bend radius190 cm B-field2.6 kGs Length50 cm Gap height2.7 cm Current5.6 kA Septum thickness2 mm Vertical incline1 deg Coil resistance12 m Ω Power consumption1.5 kW

Fast kicker

Want wide kicker plates Vertical E-field as a function of radius for different θ. Applied voltage 30 kV. Green – 45, blue – 60, red – 80 deg. Opening angle 80 deg Greater field in the center More homogenous field Probably, need to separate H and V kickers

Up to kV can be achieved with solid state short pulse generators Prices on products of Directed Energy Would require HV DC power supply ( cost not included)

Minimizing V kick

ParametersOption 1Option 2 Beta functions:  septum  kicker 101 cm 130 cm 100 cm 90 cm Kick angle16 mrad13 mrad Kicker length160 cm100 cm Kicker voltage (+/-)25 kV30 kV Orbit bump:  Number of correctors  Corrector length  Max integrated field 4 15 cm 6.9 kGs-cm 3 15 cm 9.5 kGs-cm Separation of orbits14 mm Displacement of point of injection relative to center of straight section 20.5 cm162 cm Option 1. Septum in the center of straight section Option 2. Septum between pairs of quads

3 σ size is shown Voltage± 30 kV Kicker length120 cm Distance septum-kicker60 cm

Requirements to short pulse generators Pulse Voltage± 0-30 kV Pulse flattop ns Rise/fall time20 ns Stability5% pulse-to-pulse Jitter, trigger-HV pulses Repetition rate0.1 Hz or faster Load50 Ohm, resistive Peak current600 A Peak power18 MW Power supply110 V, 60 Hz Need 4 pulsers ~ 100 % reserve for integrable optics experiments Final choice of pulse generators will determine design of the kicker

What else can be done? Reduce aperture at septum Allow to inject with 0 angle without hitting kicker plates 1 cm does not affect admittance Reduce kicker length No orbit correction? 1 sec synchrotron damping time Same kick needed

Current and future activity Contacted manufacturers about quotes for high power short pulse generators Choice of a generator determines final kicker design Electric design of stripline kicker Design of septum magnet Finalize positions of injection magnet and kicker Beam line

Thank you for attention

Backup slides

Options for short pulse generators ManufacturerMontenaIoffeFID Gmbh Pulse Voltage0-50 kV5-25 kV kV Rise/fall time5/10 ns< 20 ns10-12 ns Pulse flattop ns Jitter~ 100 ns< 1 ns CommentsElectromechanical switch Double forming line, fast semiconductor closing switch Solid state switch PriceN/ANo offer yet29 000

Simulating field in kicker SCT EM Studio Need: 50 Ohm wave impedance E < 50 kV/cm at any point