The KEK-All Ion Accelerator (KEK-AIA) · 2π/ω Acceleration region dB/dt Acceleration voltage...
Transcript of The KEK-All Ion Accelerator (KEK-AIA) · 2π/ω Acceleration region dB/dt Acceleration voltage...
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The KEK-All Ion Accelerator (KEK-AIA)
Tanuja Dixit
The Graduate University for Advanced Studies, SOKENDAIHigh Energy Accelerator Research Organization, KEK, JAPAN
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Contents• Introduction of Induction synchrotron
concept and its POP experiment• Motivation for AIA• KEK-PS Booster modification for AIA• Acceleration scenario in the AIA• New cell – 2 μsec long pulse cell• Gate control system • Summary
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Induction Synchrotron Concept
RF VoltageRF Bunch t
Voltage with gradient
Combined function
Acceleration/Confinement
Pulse voltage
For Acceleration
For Confinement
Separate function
t
t
Induction SynchrotronRF Synchrotron
Accelerator Ring
Induction cellfor acceleration
Induction cellfor confinement
Proton or Ion bunch
Vbarrier Vacctime time
Super-bunch
for proton and other ions
Difference between RF Synchrotron and Induction Synchrotron seen in Phase-space
ΔE
Induction SynchrotronRF Synchrotron
RF bunch Super-bunch
allowed maximumenergy spread
This space is not available for acceleration.
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Induction acceleration system and controls for POP
Cross-sectionof vacuum pipe
Induction Cell for Acceleration
Induction Cell for Confinement
KEK-PS
SwitchingPower Supply
Bunch Monitor
SwitchingPower Supply
DSP(1GHz)
DSP(720MHz)
Transmission line Transmission line
ΔR Monitor
Proton Beam
PatternController 1
PatternController 2
P2 Trigger Delay
Δp/p>0
S1S1
S2S2
S3S3
S4S4
dI/dtdI/dt=0=0
1)1)
2)2)
Gate pulseV
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Injection(500MeV)
Start of acceleration End of acceleration
(6GeV)
beam position (10 mm/div)
Beam current (1012/div) acceleration voltagepulse (1kV/div)
bunch signal K.Takayama et al., “Experimental Demonstration of theInduction Synchrotron”, Phys. Rev. Lett. 98, 054801 (2007)
P2 (just start of accel.) P2+400 msec near end of accel. (6GeV)
Movie of the POP experimentT.Dixit et.al. “ Adiabatic damping of bunch length in Induction Synchrotron” NIM-A 582 (2007)
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Contents• Introduction of Induction synchrotron
concept and its POP experiment• Motivation for AIA• KEK-PS Booster modification for AIA• Acceleration scenario in AIA• New cell – 2 μsec long pulse cell• Gate control system • Goal and time table
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from the Induction Synchrotron to All-ion Accelerators
Stable performance of the switching power supply from ~0Hz to 1MHzMaster trigger signal for the switching P.S. can be generated from a circulating beam signal
Allow to accelerate even quite slow particles
All-ion accelerators
A single circular strong-focusing machine can accelerate from proton to uranium,maybe including cluster ions.
from the experimental demonstration of induction acceleration in the KEK-PS
K.Takayama, K.Torikai, Y.Shimosaki, and Y.Arakida, “All Ion Accelerators”, (Patent 3896420, PCT/JP2006/308502), and J. of Appl. Phys. 101, 063304 (2007)
almost injector-freefor a low intensity beam
β 1
1 MHz
100 kHz
10 kHz
1 kHz
100 Hz
10 Hz
frf=f0
fswitch=f0
f0(revolution)=cβ/C
cβ
Synchronizationcondition
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Contents• Introduction of Induction synchrotron
concept and its POP experiment• Motivation for AIA• KEK-PS Booster modification for AIA• Acceleration scenario in AIA• New cell – 2 μsec long pulse cell• Gate control system • Summary
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Monitor system
Low current bunch monitor
Low current ΔR monitor
Main Magnet/Orbit
Low field operationCOD correction
Source/ Injection groupECR ion source
200 keV beam lineElectrostatic kickerExtraction kicker
AIAAcceleration system
Acceleration scenarioNew cell
Gate control system
AIA Working Groups
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AIA using KEK PS-Booster
extraction kicker #1 - #3
injection bump & stripping foil
extraction kicker #4
extraction bump 1
extraction bump 2
low field extraction septum high field
extraction septum
LINAC Debuncher
RF
RF KEK 12GeV-PS 500 MeV Booster Rapid Cycle Synchrotron
40 MeV BTL
Booster Ring
beam monitors
two kickers
low field septum
Induction Cells
AIA Induction Synchrotron
Booster Ring Ion Source
Electric Kicker for injection
Induction Cells
"8" figure back-leg coils
Parameters Value
Magnetic flux, Bmin 0.02916 T
Magnetic flux, Bmax 0.8583 TFrequency of magnet ramping
10 Hz
Bending radius, ρ 3.3 m
Circumference, C0 37.71 m
Maximum acceleration voltage
3.24 kV
40Argon
E. Nakamura, Y.Arakida, T.Dixit, et.al, Proceedings of PAC07, Albuquerque, NM USA
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Booster Synchrotron –A Rapid cycle synchrotron
t
Bmax
2π/ω
Acceleration region
dB/dt
Acceleration voltage requirement always transient from 0 V to peak to 0 V
Solution - Pulse density control
0( )
acdB tV C
dtρ=
( ) cosacdc ac B
B t B B tω= −
Vac=3.24 kV (peak)
for 10 Hz operation
Near injection, revolution time is large therefore longer flat acceleration voltage pulse is required
3.02.52.01.51.00.50.0
kV
50403020100 msec
2
4
681
2MHz
Designed Acc. VoltageRevolution Frequency
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Pulse density control• Trigger based system – acceleration voltage
pulses can be controlled using trigger
Acceleration voltage requirement is dynamic ∝ dB/dt
Induction acceleration cells output is fixed
Pulse density control
Δt
t
ac cellV dt VΔ
=∫V
t
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Contents• Introduction of Induction synchrotron
concept and its POP experiment• Motivation for AIA• KEK-PS Booster modification for AIA• Acceleration scenario in AIA• New cell – 2 μsec long pulse cell• Gate control system • Summary
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Confinement voltage
ACCELERATION
SCHEME for AIA
Bunch
Acceleration voltage
Prerequisites
•4 usec injected bunch
•2.2 kV and 2 usec Acceleration voltage pulse
•1.8 kV and 250nsec confinement voltage pulse
4
3
2
1
0
kV
50403020100msec
Vac(des.)Vcell
III
IIIIV
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4
3
2
1
0
kV
50403020100msec
Vac(des.)Vcell
III
IIIIV
Confinement voltage
ACCELERATION
SCHEME for AIA
Bunch
Acceleration voltage
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4
3
2
1
0
kV
50403020100msec
Vac(des.)Vcell
III
IIIIV
Confinement voltage
ACCELERATION
SCHEME for AIA
Bunch
Acceleration voltage
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4
3
2
1
0
kV
50403020100msec
Vac(des.)Vcell
III
IIIIV
Confinement voltage
ACCELERATION
SCHEME for AIA
Bunch
Acceleration voltage
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Simulation resultsNo. of particles – 10000 Initial beam Δp/p - ± 0.4% (assumption)
Momentum aperture - ± 1% Barrier voltage - 1.8 kVBeam survival & Energy gain Vs Time
100
80
60
40
20
0
Sur
viva
l %
50403020100time msec
60
40
20
0
Energy MeV/au
1.0
0.8
0.6
0.4
0.2
0.0
Nor
mal
ised
Em
ittan
ce
5040302010jitter in nsec
Normalised emittance vs jitter
100
80
60
40
20
0
Surv
ival
in %
50403020100jitter amplitude in nsec
Survival vs jitter amplitude
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Simulation results
Pulse density Vs Time
1.0
0.8
0.6
0.4
0.2
0.0
Puls
e de
nsity
1.00.80.60.40.2time msec
1.0
0.8
0.6
0.4
0.2
0.0
Puls
e de
nsity
2.01.81.61.41.21.0time msec
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Argon Ion Longitudinal phase space plots
-1.0
-0.5
0.5
1.0 dp/p %
-1000
0
1000
V
-4x10-6 -2 0 2 4sec
At injection
Blue- Barrier voltage pulse Green-Acceleration voltage pulse Red- Particles
-1.0
-0.5
0.5
1.0 dp/p %
-2000
-1000
0
1000
2000
V
-2x10-6 -1 0 1 2 sec
At 5.11 ms
-1.0
-0.5
0.5
1.0 dp/p %
-4000
-2000
0
2000
4000
V
-400x10-9 -200 0 200 400sec
At 20 ms
-1.0
-0.5
0.5
1.0dp/p %
-2000
0
2000
V
-150x10-9 -100 -50 0 50 100 150 sec
At 40 ms
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New requirement-
•Long acceleration voltage pulse
•Dynamic allocation of induction acceleration cells using DSP’s
Designed Acceleration voltage , Revolution Frequency Vs Time
3.02.52.01.51.00.50.0
kV
50403020100 msec
2
4
681
2MHz
Designed Acc. VoltageRevolution Frequency
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Contents
• Introduction of Induction synchrotron concept and its POP experiment
• Motivation for AIA• KEK-PS Booster modification for AIA• Acceleration scenario in AIA• New cell – 2 μsec long pulse cell• Gate control system • Summary
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Existing Induction acceleration cell
•Maximum rep-rate of 1 MHz
•Maximum output voltage of 2 kV with a droop of 15% in 250 ns
( ) exp where Z is total impedance (Cell + Matching resistance) L is Inductance of Cell
droop Zt L∝ −
10
5
0
-5
-10
A
7.5x10-67.06.56.05.5 sec
V0 C0 Z0(120Ω)
Z
R C
L
Induction CellV1
Switching P.S.
C11
C12
C13
C14
Transmission line(60m long)
(210 Ω matching resistance)
CT
V2
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SPICE SIMULATION
V0 C0 Z0(120Ω)
Z
R C
L
Induction CellV1
Switching P.S.
C11
C12
C13
C14 CT
V2R11
R12
R13
R14
DC P.S.
Equivalent circuit
• Flatness due to multiple reflections
•Undershoot because of downstream circuit conditions
1000
800
600
400
200
0
-200
V
4x10-63210sec
SPICEMeas.
1 TURN to 2 TURN
Demerit -
Secondary voltage becomes HALF
Vs=Vp/2
1 turn cell
L=110 μH
C=260 pF
R=330 Ω
Rm=220 Ω
2 turn cell
L=440 μH
C=180 pF
R=1280 Ω
Rm=134 Ω
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Wire Measurement
-1500
-1000
-500
0
500
1000
1500
V
6x10-6420-2 sec
Serial trigger Math signal
-2000
0
2000
V
13x10-612111098sec
Parallel trigger Math signal
GND Stand
Insulation
Ch1 Ch2
OSC
Pb1
V+V-
Wire
Wire experiment setup for 3 cells (2 turn)
InsulationGND Stand
Insulation
Ch1 Ch2
OSC
Pb1
V+V-
Wire
Wire experiment setup for 3 cells (2 turn)
Insulation
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Contents• Introduction of Induction synchrotron
concept and its POP experiment• Motivation for AIA• KEK-PS Booster modification for AIA• Acceleration scenario in AIA• New cell – 2 μsec long pulse cell• Gate control system• Summary
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5 DSP’s needs to be synchronized for start and stop of generation of SET/RESET pulse of acceleration
DSP usage
DC power supply
DSP Optical trigger unit
Switching Power Supply
Power lineAcceleration cell
beam simulator
Gate control
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Contents• Introduction of Induction synchrotron concept and its POP experiment• Motivation for AIA• KEK-PS Booster modification for AIA• Acceleration scenario in AIA• New cell – 2 μsec long pulse cell• Gate control system • Summary
beamcommission
modification works•beam line
•replacement of RF by IAS
ECR ion source cluster ion source
Accelerator09082007Year
beamcommission
modification works•beam line
•replacement of RF by IAS
ECR ion source cluster ion source
Accelerator09082007Year
The KEK-All Ion Accelerator �(KEK-AIA)ContentsInduction Synchrotron Concept Induction acceleration system and controls for POP ContentsContentsAIA using KEK PS-BoosterPulse density controlContentsSimulation resultsSimulation resultsNew requirement-ContentsContentsDSP usage Contents