BEAM TRANSFER CHANNELS, BEAM TRANSFER CHANNELS, INJECTION AND EXTRACTION SYSTEMS OF NICA ACCELERATOR...
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Transcript of BEAM TRANSFER CHANNELS, BEAM TRANSFER CHANNELS, INJECTION AND EXTRACTION SYSTEMS OF NICA ACCELERATOR...
BEAM TRANSFER CHANNELS,
INJECTION AND EXTRACTION SYSTEMSOF NICA ACCELERATOR COMPLEX
Tuzikov A.,JINR, Dubna, Russia
NICA beam transfers
Beam transfer from HILAC to Booster
• HILAC-Booster transport channel;• Booster injection system.
Beam transfer from Booster to Nuclotron
• Booster fast extraction system;• Booster-Nuclotron transport channel;• Nuclotron high energy beam injection system.
Beam transfer from Nuclotron to Collider
• Nuclotron fast extraction system;• Nuclotron-Collider transport channel;• Collider injection system.
2NICA MAC 2015
Beam transfer from HILAC to Booster
Goals
•Accumulation of required intensity of ions in Booster by means of several methods of beam injection.
Beam parametersSort of ions Au31+ (Au51+, Au65+)Energy, MeV/u 3.2Magnetic rigidity, T m 1.6Electric rigidity, MV 40Ion number 2∙109
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HILac
Booster
NICA MAC 2015
• The beam transport with minimal ion losses.• The beam debunching.• The beam matching.• Separation and adsorption of neighbor
charge states of ions.• Providing different schemes of the beam
injection into the Booster.
Main goals
HILAC-Booster beam transport channel
4
IES
• Length of first straight line of the channel? The debuncher should be located in non-dispersive region.
• Angle between final straight line of the channel and 1st straight line of Booster? There are two concurrent tasks: to minimize length of electrostatic septum of Booster injection system and to minimize final ‘dead zone’ of the channel.
Optimization of the channel geometry
NICA MAC 2015
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Channel geometry
Whole channel Part inside Synchrophasotron yoke
HILAC-Booster beam transport channel
NICA MAC 2015
Parameters of main elements
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HILAC-Booster beam transport channel
Q1 Q2 Q3 Deb. BM2 Q7 Q8 Steer.
Available at JINR
Q4 Q5 Q6BM1
Magnetic element Dipole Quadrupole
Effective length, m 0.647 0.29
Max field (gradient), T (T/m)
1.21 10
Gap (diameter), mm 76 95
Debuncher
Designed by Bevatech team
Inner length, m 0.49
Frequency, MHz 100.625
Max effective voltage, kV
340
NICA MAC 2015
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HILAC-Booster beam transport channel
1 2 4
1) Betatron matching of the beam with Booster lattice functions (section 1-2).2) Matching of horizontal dispersion of the beam with Booster (section 2-4).3) Focusing of the beam to avoid ion losses inside the debuncher (section 1-2).4) Vertical focusing of the beam to avoid ion losses inside dipoles (section 1-3).5) Separation of charge states of ions (section 1-3).
Concept of optical system tuning
Q1 Q2 Q3 Deb. BM2 Q7 Q8 Steer.Q4 Q5 Q6BM13
NICA MAC 2015
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Horizontal dispersion
HILAC-Booster beam transport channel
Beta functions
Beam dynamics simulations
NICA MAC 2015
• The beam injection with minimal ion losses.• The beam injection by the following methods:
single-turn injection, multiturn injection, multiple injection.
Goals
Booster injection system
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• Accumulation of ions in horizontal phase plane.• Closed orbit bump (for multiturn and multiple
injections).• Rapid change of fields in the system elements
(for more compact filling of the horizontal phase plane in case of multiturn and multiple injections).
Features
1st straight section
NICA MAC 2015
Parameters of elements
Length, m Gap, mm X1, mm X2, mm Max voltage, kV
IK1 0,5 102 -51 +51 40
IK2 0,8 93 -36 +57 40
IK3 0,5 102 -51 +51 60
IES 2 35 [+40; +205] [+75; +240] 120
Booster injection system
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IK1 IES IK2 IK3
NICA MAC 2015
Injection electrostatic septum IES
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Booster injection system
NICA MAC 2015
Electric injection kickers IK1 – IK3
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Booster injection system
NICA MAC 2015
Goals
•Transfer of the beam with parameters which can be altered in wide ranges due to 1) use of different schemes of beam injection into Booster and 2) use of an electron cooling system.
•Ion stripping to a maximum charge state.
•Control of the beam emittances.
Sort of ions:
before stripping station
after stripping station
Au31+ (Au51+, Au65+)
Au79+
Maximum energy of ions inside the channel, MeV/u 685Maximum magnetic rigidity of ions inside the channel, T m:
before stripping station
after stripping station
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11
Ion number 1.5∙109
Beam Parameters
Beam transfer from Booster to Nuclotron
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Booster
Nuclotron
NICA MAC 2015
• Fast extraction of the beam with minimal ion losses.
Goals
Booster fast extraction system
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• Closed orbit bump (for required kick’s minimization).
Features
Kicker
Magnetic septum
3rd straight section
NICA MAC 2015
Parameters of elements
Length, m 3
Max magnetic field, T 0.13
Aperture, mm×mm 80×90
Pulse duration, μs: rise plateau fall
0.250.5~10
15
Booster fast extraction system
Kicker
Length, m 2.5
Max magnetic field, T 1
Aperture, mm×mm 35×40
Septum thickness, mm
3
Pulse shape semisinusoidal
Pulse duration, μs ~ 10
Septum
NICA MAC 2015
Kicker
16
Booster fast extraction system
NICA MAC 2015
40м
м
d=80мм
beam
Extracted beam area
Injected beam area
Magnetic field (T): measurements
Magnetic field (T): simulations Magnetic field homogeneity
Booster fast extraction system
Kicker
NICA MAC 2015
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Septum
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Booster fast extraction system
NICA MAC 2015
The current-carrying plate and the shield Lines of force
Magnetic field (T) Surface current density (MA/m).
Booster fast extraction system
Septum
NICA MAC 2015
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Magnetic field distribution along vertical line Magnetic field distributions along horizontal line
Septum
Booster fast extraction system
NICA MAC 2015
Magnetic field distribution between the plate and the shield: simulations and measurements
Magnetic field distributions along longitudinal line
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Goals
Booster-Nuclotron beam transport channel
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• The beam transport with minimal ion losses.• Ion stripping to the maximum charge state.• Separation of neighbor charge states. Estimates of ion stripping at energy of 580
MeV/u: 100% Au31+ → 80% Au79+, ~20% Au78+. Due to high intensity of Au78+ ions they have to be extracted from the channel to an absorber.
• Minimization of emittance growth and control of emittances of the beam injected into Nuclotron.
NICA MAC 2015
Booster-Nuclotron beam transport channel
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Channel geometry
View from above
Vertical profile
NICA MAC 2015
Booster-Nuclotron beam transport channel
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Preliminary parameters of magnetic elements
Magnetic element
Type Effective length, m
Max. magnetic field (gradient), T (T/m)
BM1 – BM4 sector dipole 1.7 1.8
LM Lambertson magnet 1.5 1.5
Q1, Q2 quadrupole 0.6 30
Q3 – Q6 quadrupole 0.4 20
NICA MAC 2015
Booster-Nuclotron beam transport channel
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Generalized optimization of optical system
• Multiple scattering and energy straggling of ions at the stripping target.• Coupled motion in tilt bending magnets.• Mismatch of the beam with Nuclotron.
Transverse and longitudinal emittance growth
1) Minimum growth of emittances after the beam filamentation inside Nuclotron.2) Criteria of transverse emittances’ control: for example, equality of horizontal and vertical emittances to each other.3) Full separation of Au78+ ions from the Au79+ beam at the entry of the Lambertson magnet. 4) Minimum beam sizes along the channel.5) Criteria of quadrupole gradients’ control: for example, minimization of gradients.
Criteria of optimality
There are optimal settings of the optical system (i.e. optimal gradients of the quadrupoles) for any working regime (initial parameters of a beam). But it is not for practical use.
Ways to reduce number of independent variables and number of working regimes:1) Use of one setting for many working regimes.2) Use of settings which are not optimal but close to global optimum.
Concept of optical system tuning
NICA MAC 2015
• Single-turn injection of the beam with minimal ion losses.
Goals
Nuclotron high energy beam injection system
25
Parameters of elements
Length, m 3
Max magnetic field, T 0.06
Aperture, mm×mm 100×60
Pulse duration, μs: rise plateau fall
~100.50.25
Kicker
Length, m 1; 1.5; 0.5
Max magnetic field, T 1.2; 1.2; 1
Septum thickness, mm
15; 15; 5
Power supply system cyclic, cycle duration ~1 s
Lambertson magnet (three sections)
NICA MAC 2015
Beam transfer from Nuclotron to Collider
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Goals•Alternate filling of the
Collider rings.•Accumulation of required
intensity of ions (with help of barrier bucket system and beam cooling systems of Collider).
Sort of ions Au79+
Energy of ions, GeV/u 1 ÷ 4.5Magnetic rigidity of ions, T m
14 ÷ 45
Ion number 1∙109
Beam Parameters
NICA MAC 2015
• Fast extraction of the beam with minimal ion losses.
Goals
Nuclotron fast extraction system
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Parameters of elements
Length, m 3
Max magnetic field, T 0.13
Aperture, mm×mm 110×70
Pulse duration, μs: rise plateau fall
≤ 0.2≥ 0.2~10
Kicker
Length, m 0.5; 2.5
Max magnetic field, T 1; 1.6
Septum thickness, mm
5; 10
Power supply system cyclic, serial to dipole magnets
Lambertson magnet (two sections)
NICA MAC 2015
Goals
Nuclotron-Collider beam transport channel
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• The beam transport with minimal ion losses.• The beam matching with lattice functions of the Collider rings except vertical
dispersion which suppression is sufficient.
NICA MAC 2015
Parameters of pulsed magnet elements
Nuclotron-Collider beam transport channel
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Magnetic element Number Effective length, m Max. magnetic field (gradient), T (T/m)
Horizontal bending magnet
19 2 1.5
Vertical bending magnet 12 2 1.5Correcting bending
magnet2 1 1.5
Quadrupole 45 0.5 20
Designed by BINP team
NICA MAC 2015
Vertical dispersion suppression
Nuclotron-Collider beam transport channel
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Suppresion vs matching• Vertical dispersion is not fully suppressed in Collider. Value of the dispersion in the beam
injection point is equal to 0.03 m.• If the beam is injected with zero dispersion then the beam emittance grows due to phase
density filamentation. But this effect is negligibly small.
How to suppress vertical dispersion• The best solution is to provide achromatic transfer of the beam from Nuclotron to median
planes of the Collider rings in the common part of the channel. But lattice variants which meet condition of achromatic transfer have not been found.
• Vertical dispersion can be suppressed by means of optical sections with vertical bending magnets located in branches of the channel. The most preferable locations of dispersion suppressors are long straight sections of the channel branches.
What if vertical dispersion will not be suppressed• Since vertical dispersion suppressors make the channel lattice too complex, lattice without suppressors is proposed as an alternative.• Beam dynamics simulations have shown that vertical emittance growth due to unsuppressed dispersion does not exceed 10%.
NICA MAC 2015
Variant 1 of vertical dispersion suppression
Nuclotron-Collider beam transport channel
31
• Minimization of vertical dispersion invariant () at the exit of the common part of the channel is critical.• Low values of vertical beta functions are required inside suppressors.
Common part
Dispersion suppressor
NICA MAC 2015
Variant 2 of vertical dispersion suppression
Nuclotron-Collider beam transport channel
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• Minimization of vertical dispersion invariant at the exit of common part of the channel is optional.• There are no limitations on values of vertical beta functions inside suppressors. Vertical dispersion suppression is provided by tuning betatron phase advance between parts of the suppressors.
Common part
Dispersion suppressor
NICA MAC 2015
Optical system
Nuclotron-Collider beam transport channel
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Tuning of optical system • Section E-C1: minimization of .• Sections C1-L1 and R1-R2: matching of , and ; suppression of .• Sections L1-LI and C1-R1: matching of horizontal dispersion invariant .• Section R2-RI: minimization of .
NICA MAC 2015
Length, m 4.6
Max magnetic field, T 0.13
Aperture, mm×mm 80×60
Pulse duration, ns: total plateau
< 900150-200
Kicker
Parameters of elements
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Collider injection system
Length, m 1.5
Max magnetic field, T 1
Aperture, mm×mm 45×45
Septum thickness, mm
3
Pulse shape semisinusoidal
Pulse duration, ms ~ 10
Septum
• Single-turn injection of the beam with minimal ion losses.
Goals
NICA MAC 2015
THANK YOU FOR ATTENTION
Additional slides
Electric injection kickers IK1 – IK3
Power supplies
Pulse
Trise < 50 ms
Tpl 8 ÷ 30 µs
Tfall ≤ 0.1 µs
IK1 IK2 IK3
Plate №1 Plate №2 Plate №1 Plate №2 Plate №1 Plate №2
40 kV 0 kV 40 kV 15 kV 60 kV 15 kV
37
Booster injection system
NICA MAC 2015
Electric injection kickers IK1 – IK3
Impulse on plate №1
Difference impulse
U
t
Upl,1
U
t
Upl,2
U
t
Upl,1
- Upl,2
T1st pl
T2nd pl
Trise
Upl,1
Impulse on plate №2
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Booster injection system
NICA MAC 2015
• Beam duration – less than 8.5 µs.• Horizontal emittance – 15 ÷ 160 π·mm·mrad.• Vertical emittance – 15 π·mm·mrad.
Voltage, kV Electric field, kV/cm Angle, mradIK1 0 0 0
IK2 0 0 0
IK3 37 ÷ 54 3.6 ÷ 5.3 4.7 ÷ 6.8
Main injection method and its modification
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Booster injection system
NICA MAC 2015
Concept of multiturn injection
•Accumulation of ions during several periods of the beam revolution.•Horizontal emittance of stored beam depends on number of turns and horizontal
betatron tune.•Horizontal emittance for different injection schemes – 65 ÷ 120 π·mm·mrad.
3
0,1,2
3
septum
X
X’
3 1,2
2
0,1,2
3
2
0,1
2
septum
X
X’
1
0
1
2
Double-plateau pulseSingle-plateau pulse
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Booster injection system
NICA MAC 2015
Concept of multiple injection•Accumulation of ions by multiple repetitions of single-turn injections.•Varying the horizontal phase portrait of the injecting beam allows more compact filling of the phase
plane. •Horizontal emittance of the stored beam depends on number of injection repetitions.•Horizontal emittance for different injection schemes – 50 ÷ 135 π·mm·mrad.
Double-plateau pulseSingle-plateau pulse
1
0
septum
X
X’
0
1
1
< 0
1
0
septum
X
X’
0
0
1
1
< 0
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Booster injection system
NICA MAC 2015
42
Booster fast extraction system
Closed orbit bump
Beam extraction
NICA MAC 2015
Booster-Nuclotron beam transport channel
43
Beam dynamics example: single turn injection into Booster; no beam cooling
• Initial horizontal emittance εx,0 (r.m.s.): 0.14 π∙mm∙mrad. • Initial vertical emittance εy,0 (r.m.s.): 0.14 π∙mm∙mrad.• Initial momentum spread σp,0 (r.m.s.): 3∙10-4.• Stripper target: carbon, thickness 125 μm.
Working regime of the channel
Lattice functions
NICA MAC 2015
Booster-Nuclotron beam transport channel
44
Beam dynamics example
Separation of Au78+ ions
NICA MAC 2015
Magnetic elements
Nuclotron high energy beam injection system
45
Beam injection
Kicker Lambertson magnet (three sections)
?
NICA MAC 2015
46
Collider injection system
Kicker with correcting unit
Magnetic fields in kicker units Effective magnetic field acting on ions
NICA MAC 2015
47
Beam extraction
Nuclotron fast extraction system
NICA MAC 2015