BEAM TRANSFER CHANNELS, BEAM TRANSFER CHANNELS, INJECTION AND EXTRACTION SYSTEMS OF 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. 2 NICA 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 parameters Sort of ionsAu 31+ (Au 51+, Au 65+ ) Energy, MeV/u3.2 Magnetic rigidity, T m1.6 Electric rigidity, MV40 Ion number2∙ 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 1 st 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

5 Channel geometry Whole channelPart inside Synchrophasotron yoke HILAC-Booster beam transport channel NICA MAC 2015

Parameters of main elements 6 HILAC-Booster beam transport channel Q1Q2Q3Deb.BM2Q7Q8Steer. Available at JINR Q4Q5Q6BM1 Magnetic element DipoleQuadrupole Effective length, m Max field (gradient), T (T/m) Gap (diameter), mm7695 Debuncher Designed by Bevatech team Inner length, m 0.49 Frequency, MHz Max effective voltage, kV340 NICA MAC 2015

7 HILAC-Booster beam transport channel )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 Q1Q2Q3Deb.BM2Q7Q8Steer. Q4Q5Q6BM1 3 NICA MAC 2015

8 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 9 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 1 st straight section NICA MAC 2015

Parameters of elements Length, mGap, mmX 1, mmX 2, mmMax voltage, kV IK10, IK2 0, IK30, IES235[+40; +205][+75; +240] Booster injection system 10 IK1 IES IK2 IK3 NICA MAC 2015

Injection electrostatic septum IES 11 Booster injection system NICA MAC 2015

Electric injection kickers IK1 – IK3 12 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 Au 31+ (Au 51+, Au 65+ ) Au 79+ Maximum energy of ions inside the channel, MeV/u685 Maximum magnetic rigidity of ions inside the channel, T m: before stripping station after stripping station Ion number1.5∙10 9 Beam Parameters Beam transfer from Booster to Nuclotron 13 Booster Nuclotron NICA MAC 2015

Fast extraction of the beam with minimal ion losses. Goals Booster fast extraction system 14 Closed orbit bump (for required kick’s minimization). Features Kicker Magnetic septum 3 rd straight section NICA MAC 2015

Parameters of elements Length, m 3 Max magnetic field, T 0.13 Aperture, mm×mm80×90 Pulse duration, μs: rise plateau fall ~10 15 Booster fast extraction system Kicker Length, m 2.5 Max magnetic field, T 1 Aperture, mm×mm35×40 Septum thickness, mm3 Pulse shapesemisinusoidal Pulse duration, μs~ 10 Septum NICA MAC 2015

Kicker 16 Booster fast extraction system NICA MAC 2015

Magnetic field (T): measurements Magnetic field (T): simulations Magnetic field homogeneity Booster fast extraction system Kicker NICA MAC

Septum 18 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

Magnetic field distribution along vertical lineMagnetic 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 20

Goals Booster-Nuclotron beam transport channel 21 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% Au 31+ → 80% Au 79+, ~20% Au 78+. Due to high intensity of Au 78+ 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 22 Channel geometry View from above Vertical profile NICA MAC 2015

Booster-Nuclotron beam transport channel 23 Preliminary parameters of magnetic elements Magnetic element TypeEffective length, mMax. magnetic field (gradient), T (T/m) BM1 – BM4sector dipole LMLambertson magnet Q1, Q2quadrupole0.630 Q3 – Q6quadrupole NICA MAC 2015

Booster-Nuclotron beam transport channel 24 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 Au 78+ ions from the Au 79+ 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×mm100×60 Pulse duration, μs: rise plateau fall ~ Kicker Length, m 1; 1.5; 0.5 Max magnetic field, T 1.2; 1.2; 1 Septum thickness, mm15; 15; 5 Power supply systemcyclic, cycle duration ~1 s Lambertson magnet (three sections) NICA MAC 2015

Beam transfer from Nuclotron to Collider 26 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 ionsAu 79+ Energy of ions, GeV/u1 ÷ 4.5 Magnetic rigidity of ions, T m14 ÷ 45 Ion number1∙10 9 Beam Parameters NICA MAC 2015

Fast extraction of the beam with minimal ion losses. Goals Nuclotron fast extraction system 27 Parameters of elements Length, m 3 Max magnetic field, T 0.13 Aperture, mm×mm110×70 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, mm5; 10 Power supply systemcyclic, serial to dipole magnets Lambertson magnet (two sections) NICA MAC 2015

Goals Nuclotron-Collider beam transport channel 28 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 29 Magnetic elementNumberEffective length, mMax. magnetic field (gradient), T (T/m) Horizontal bending magnet Vertical bending magnet Correcting bending magnet211.5 Quadrupole Designed by BINP team NICA MAC 2015

Vertical dispersion suppression Nuclotron-Collider beam transport channel 30 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 Common part Dispersion suppressor NICA MAC 2015

Variant 2 of vertical dispersion suppression Nuclotron-Collider beam transport channel 32 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 33 NICA MAC 2015

Length, m 4.6 Max magnetic field, T 0.13 Aperture, mm×mm80×60 Pulse duration, ns: total plateau < Kicker Parameters of elements 34 Collider injection system Length, m 1.5 Max magnetic field, T 1 Aperture, mm×mm45×45 Septum thickness, mm3 Pulse shapesemisinusoidal Pulse duration, ms~ 10 Septum Single-turn injection of the beam with minimal ion losses. Goals NICA MAC 2015

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Additional slides

Electric injection kickers IK1 – IK3 Power supplies Pulse T rise < 50 ms T pl 8 ÷ 30 µs T fall ≤ 0.1 µs IK1IK2IK3 Plate №1Plate №2Plate №1Plate №2Plate №1Plate №2 40 kV0 kV40 kV15 kV60 kV15 kV 37 Booster injection system NICA MAC 2015

Electric injection kickers IK1 – IK3 Impulse on plate №1 Difference impulse Impulse on plate №2 38 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, kVElectric field, kV/cmAngle, mrad IK1 000 IK2 000 IK3 37 ÷ ÷ ÷ 6.8 Main injection method and its modification 39 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. Double-plateau pulseSingle-plateau pulse 40 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 41 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 ε x,0 (r.m.s.): 0.14 π∙mm∙mrad. Initial vertical emittance ε y,0 (r.m.s.): 0.14 π∙mm∙mrad. Initial momentum spread σ p,0 (r.m.s.): 3∙ 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 Au 78+ ions NICA MAC 2015

Magnetic elements Nuclotron high energy beam injection system 45 Beam injection KickerLambertson 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