Download - Injection to IOTA ring
Injection to IOTA ring
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
ParameterValueEnergy150 MeVNumber of e in bunch109Circumference40 mBending dipole field0.7 TRF voltage50 kVMax x, y9 m, 4 mMin x, y0.1 m, 0.25 mMomentum compaction0.14Betatron tuneQx,Qy = 3.2 (2.4 to 3.6)Equilibrium transverse emittance0.06 m (non-normalized)Synchrotron damping time~ 1 sLattice 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 (, , 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 isolation
Lambertson
Injection in horizontal plane
Possible problems with field leakage
Septum thickness determined by max current density
Pulsed device
Injection in vertical plane
A bigger (more expensive) device
Septum thickness
Can be DC
DC Lambertson septum
DC offers higher stability than pulsed devices
Lambertson septum has simpler design
Gap increased to fit for proton injection
Power consumption ~ 1.5 kW
Beam separation:Septum thickness 2mm +thickness of vacuum chambers +reserve -> ~ 10 mm
ParameterValueBend angle15 degBend radius190 cmB-field2.6 kGsLength50 cmGap height2.7 cmCurrent5.6 kASeptum thickness2 mmVertical incline1 degCoil resistance12 mPower consumption1.5 kWFast kicker
Stripline
Length:
Separation of plates:
Bend angle:
Pulse duration:
Will be used for nonlinear optics experiment >must have enough power for them
At least 8 mrad
Should have 50 wave impedance
Can fit inside quadrupole magnets
Want wide kicker plates
Vertical E-field as a function of radius for different .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 30-40 kV can be achieved with solid stateshort pulse generators
Prices on products of Directed Energy
Would require HV DC power supply ( cost not included)
Cost1500350060001000035004500750011500
Peak Voltage, V
Cost, $
Minimizing Vkick
Vary kicker length and position, position of septum, number, strength and position of dipole correctors
Constraints:
Min separation of beams 10 mm
Particles should not hit kicker plates, 2 mm reserve
Orbit of circulating beam should be no closer than 6 to physical aperture
Lengths: septum 50 cm, correctors 15 cm
Length of kicker < 2 m
integrated field of dipole correctors 10 kGs-cm
Option 1. Septum in the center of straight section
Option 2. Septum between pairs of quads
3 size is shown
Voltage 30 kVKicker length120 cmDistance septum-kicker60 cmRequirements to short pulse generators
Pulse Voltage 0-30 kVPulse flattop30-100 nsRise/fall time20 nsStability5% pulse-to-pulseJitter, trigger-HV pulses or lessRepetition rate0.1 Hz or fasterLoad50 Ohm, resistivePeak current600 APeak power18 MWPower supply110 V, 60 HzNeed 4 pulsers
~ 100 % reserve for integrableoptics experiments
Final choice of pulse generators willdetermine design of the kicker
What else can be done?
Reduce aperture at septum
Allow to inject with 0 anglewithout 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 GmbhPulse Voltage0-50 kV5-25 kV2.5-25 kVRise/fall time5/10 ns< 20 ns10-12 nsPulse flattop50-100 ns50-100 ns50-100 nsJitter~ 100 ns< 1 ns< 1 nsCommentsElectromechanical switchDouble forming line, fast semiconductor closing switchSolid state switchPriceN/ANo offer yet29 000Simulating field in kicker
SCT EM Studio
Need:
50 Ohm wave impedance
E < 50 kV/cm at any point
0
1
2
5
10
15
20
25
E
y
r
80
180
p
,
E
y
r
p
3
,
E
y
r
p
4
,
r
V
source
V
k
w
160
,
(
)
2
25.02
=
:=
50
100
150
200
0
20
40
60
16 mrad
8 mrad
Kicker Length, cm
Required power supply, kV