1. 1 Machine Advisory Committee Video-Conference JINR, Dubna May 20, 2009 Concept and Status of The NICA Project Nuclotron-based Ion Collider fAcility I.Meshkov for NICA Group

2. 2 Contents Introduction: Development of the NICA Concept and Technical Design Report 1. NICA scheme & layout 2. Heavy ions in NICA 2.1. Injector, Booster, Nuclotron 2.2. Collider 3. Polarized particle beams in NICA 4. NICA TDR status and nearest plans, problems to be solved Conclusion I.Meshkov, NICA Status MAC Video-Conference JINR, May 20, 2009

3. 3 May 2009: NICA TDR & MPD CDR will be completed I.Meshkov, NICA Status MAC Video-Conference JINR, May 20, 2009 January 2008 Conceptual Design Report of Nuclotron-based Ion Collider fAcility (NICA) (Short version) January 2009 Introduction: Development of the NICA Concept and TDR

4. 4 I.Meshkov, NICA Status MAC Video-Conference JINR, May 20, 2009 The Project goals formulated in CDR remain: 1a) Heavy ion colliding beams 197 Au 79+ x 197 Au 79+ at  s NN = 4  11 GeV (1  4.5 GeV/u ion kinetic energy ) and L average = 1  10 27 cm -2  s -1 (at  s NN = 9 GeV/u) 1b) Light-Heavy ion colliding beams 2) Polarized beams of protons and deuterons: p  p   s NN = 12  25 GeV (5  12.6 GeV kinetic energy ) d  d   s NN = 4  13.8 GeV (2  5.9 GeV/u ion kinetic energy ) Introduction: Development of the NICA Concept and Technical Design Report (Contnd)

5. 5 I.Meshkov, NICA Status MAC Video-Conference JINR, May 20, 2009 1. NICA scheme & layout 2.3 m 4.0 m Booster Synchrophasotron yoke Nuclotron Existing beam lines (solid target exp-s) Collider C = 251 m MPD Spin Physics Detector (SPD)

6. 6 1. NICA scheme & layout (Contnd) I.Meshkov, NICA Status MAC Video-Conference JINR, May 20, 2009 “Old” Linac LU-20 KRION + “New” HILAC Booster Nuclotron Collider MPD SPD Beam dump

7. 7 1) to avoid a big problem of “chemistry kitchen” with radioactive Uranium oxides at ion sourсe, etc.; I.Meshkov, NICA Status MAC Video-Conference JINR, May 20, 2009 2. Heavy ions in NICA What is new? The injection chain remains the same : Injector  Booster  Nuclotron But! Uranium ions 238 U 32+ to be generated with KRION source have been replaced by Gold ions 197 Au 32+. This step allows us 2.1. Injector, Booster, Nuclotron 2) to increase ion energy accelerated in the Booster up to 608 MeV/u…

8. 8 3) …that increases ion stripping efficiency (after extraction from the Booster and before injection into Nuclotron) up to 80% or more; I.Meshkov, NICA Status MAC Video-Conference JINR, May 20, 2009 What is new? 2.1. Injector, Booster, Nuclotron …this step allows us 2. Heavy ions in NICA (Contnd) 5) the bunch compression: RF voltage jump for the bunch “overturn” in phase space in Nuclotron will be replaced by RF phase jump. What is new: 4) and allows us to diminish the number of injection pulses into the Booster to ONE PER CYCLE (2-3 pulses injection regime will be reserved “for safety”);

9. 9 I.Meshkov, NICA Status MAC Video-Conference JINR, May 20, 2009 2.1. Injector, Booster, Nuclotron 2. Heavy ions in NICA (Contnd) What is new? Booster (25 Tm) 1(2-3) single-turn injection, storage of 2 (4-6)×10 9, acceleration up to 100 MeV/u, electron cooling, acceleration up to 608 MeV/u Nuclotron (45 Tm) injection of one bunch of 1.1×10 9 ions, acceleration up to 1  4.5 GeV/u max. Collider (45 Tm) Storage of 17 (20) bunches  1  10 9 ions per ring at 1  4.5 GeV/u, electron and/or stochastic cooling Stripping (80%) 197 Au 32+  197 Au 79+ 2х17 (20) injection cycles Injector: 2×10 9 ions/pulse of 197 Au 32+ at energy of 6.2 MeV/u IP-1 IP-2 Two superconducting collider rings Bunch compression (RF phase jump)

10. 10 I.Meshkov, NICA Status MAC Video-Conference JINR, May 20, 2009 2. Heavy ions in NICA (Contnd) Bunch parameters dynamics in the injection chain 2.1. Injector, Booster, Nuclotron StageE MeV/u  unnorm  mm  mrad  p/pl bunch m Intensity loss,% Space charge  Q Injection (after bunching on 4 th harmonics 6.2101.3E-36100.022 After cooling (h=1)1002.453.8E-47.17<100.016 At extraction6080.893.2E-43.1 0.0085 Injection (after stripping) 5940.893.4E-43.1<200.051 After acceleration35000.251.5E-42<1 0.0075 At extraction35000.251  10 -3 0.5  Loss = 40% N extr = 1E9 0.03

11. 11 I.Meshkov, NICA Status MAC Video-Conference JINR, May 20, 2009 2. Heavy ions in NICA (Contnd) Bunch compression in Nuclotron 2.1. Injector, Booster, Nuclotron Phase space portraits of the bunch Bunch rotation by “RF amplitude jump” 15  120 kV , 10 deg./div E – E 0, 2 GeV/div 1 2

12. 12 I.Meshkov, NICA Status MAC Video-Conference JINR, May 20, 2009 2. Heavy ions in NICA (Contnd) Bunch compression in Nuclotron 2.1. Injector, Booster, Nuclotron time, 0.1 sec/div.  E_r.m.c. 200 MeV/div.  _r.m.s. 5 deg./div. (1 deg.  0.7 m)  _r.m.s. 0.5 eV  sec/div E – E 0, 2 GeV/div Phase space portraits of the bunch (RF “phase jump”  = 180 0 ) , 50 deg./div

13. 13 I.Meshkov, NICA Status MAC Video-Conference JINR, May 20, 2009 2. Heavy ions in NICA (Contnd) 2.1. Injector, Booster, Nuclotron Time Table of The Storage Process 0 0.5 1.5 3 4 t, [s] 1 (2-3) injection cycles, electron cooling (?) electron cooling 0 0.5 1.5 3 4 5 6 7 t, [s] Nuclotron magnetic field Arbitrary units injection bunch compression, extraction Extraction, stripping to 197 Au 79 + Booster magnetic field 34 injection cycles to Collider rings of 1  10 9 ions 197 Au 79+ per cycle 1.7  10 10 ions/ring

14. 14 I.Meshkov, NICA Status MAC Video-Conference JINR, May 20, 2009 2. Heavy ions in NICA (Contnd) What is new? 2.2. Collider The previous scheme: bunch by bunch injection, 17 bunches, bunch number is limited by kicker pulse duration, bunch compression in Nuclotron is required (!) Electron and/or stochastic cooling for luminosity preservation. The new scheme: Injection and storage with barrier bucket technique and cooling of a coasting (!) beam, 20 bunches, bunch number is limited by interbunch space in IP straight section, bunch compression in Nuclotron is NOT required (!) Electron and/or stochastic cooling for storage and luminosity preservation, bunch formation after storage are required.

15. 15 I.Meshkov, NICA Status MAC Video-Conference JINR, May 20, 2009 2. Heavy ions in NICA (Contnd) What is new? 2.2. Collider A decrease of intrabunch space with “barrier bucket” (BB) method: Periodic voltage pulses applied to a low quality cavity when stochastic or electron cooling is ON. Revolution period V(t) Stack Injection time Cooling’ is ON Cavity voltage (  p) ion The method was tested experimentally at ESR (GSI) with electron cooling (2008). NICA: T revolution = 0.85  0.96  s, V BB  10 kV

16. 16 Ring circumference, [m]251.52 B  max [ T  m ]45.0 Ion kinetic energy (Au79+), [GeV/u]1.0  4.56 Dipole field (max), [ T ]4.0 Quad gradient (max), [ T/m ]29.0 Number of dipoles / length24 / 3.0 m Number of vertical dipoles per ring2 x 4 Number of quads / length32 / 0.4 m Long straight sections: number / length2 x 48.0 m Short straight sections: number / length,4 x 8.8 m I.Meshkov, NICA Status MAC Video-Conference JINR, May 20, 2009 2. Heavy ions in NICA (Contnd) 2.2. Collider General Parameters

17. 17 I.Meshkov, NICA Status MAC Video-Conference JINR, May 20, 2009 2. Heavy ions in NICA (Contnd) 2.2. Collider General parameters (Contnd) βx_max / βy_max in FODO period, m16.8 / 15.2 Dx_max / Dy_max in FODO period, m5.9 / 0.2 βx_min / βy_min in IP, m0.5 / 0.5 Dx / Dy in IP, m0.0 / 0.0 Free space at IP (for detector)9 m Beam crossing angle at IP0 Betatron tunes Qx / Qy5.26 / 5.17 Chromaticity Q’x / Q’y-12.22 / -11.85 Transition energy,  _tr / E_tr4.95 / 3.012 GeV/u RF system harmonics amplitude, [kV] 102 100 Vacuum, [ pTorr ]100  10

18. 18 2. Heavy ions in NICA (Contnd) 2.2. Collider General parameters (Contnd) Resonance diagram I.Meshkov, NICA Status MAC Video-Conference JINR, May 20, 2009 Working point 5.26 / 5.17

19. 19 Energy, GeV/u1.03.5 Ion number per bunch1E9 Number of bunches per ring17 (20) Rms unnormalized beam emittance,  ∙mm mrad3.80.25 Rms momentum spread1E-3 Rms bunch length, m0.3 Luminosity per one IP, cm -2 ∙s -1 0.75E261.1E27 Incoherent tune shift  Q bet 0.0560.047 Beam-beam parameter  0.00260.0051 IBS growth time, s 65050 I.Meshkov, NICA Status MAC Video-Conference JINR, May 20, 2009 2. Heavy ions in NICA (Contnd) 2.2. Collider General parameters (Contnd) Collider beam parameters and luminosity

20. 20 dN/dx, arb. units Under cooling, equilibrium with IBS Nongaussian distribution I.Meshkov, NICA Status MAC Video-Conference JINR, May 20, 2009 2. Heavy ions in NICA (Contnd) 2.2. Collider dN/dx, arb. units Before cooling Gaussian distribution IBS Heating and cooling – bunch density evolution at electron cooling BETACOOL Alexander Smirnov

21. 21 T e  = 10 eV I.Meshkov, NICA Status MAC Video-Conference JINR, May 20, 2009 2. Heavy ions in NICA (Contnd) 2.2. Collider BETACOOL simulation Parameters ion beam: 197 Au 79+ at 3.5 GeV/u,  initial =0.5  ∙mm∙mrad, (  p/p) = 1∙10 -3 electron beam: I e = 0.5 A, r e = 2 mm, T e|| = 5 meV;  = 0.024 (6 m/250 m) IBS Heating and cooling – luminosity evolution at electron cooling B [kG] 8 6 4 2 6 Luminosity [1E27 cm -2 ∙s -1 ] 4 2 0 Conclusion: Electron magnetization is much more preferable

22. 22 I.Meshkov, NICA Status MAC Video-Conference JINR, May 20, 2009 2. Heavy ions in NICA (Contnd) 2.2. Collider IBS Heating and cooling – luminosity evolution at electron cooling T e  = 10 eV BETACOOL simulation B = 3 kG 4 Luminosity [1E27 cm -2 ∙s -1 ] 2 0 Parameters (as on previous slide): ion beam: 197 Au 79+ at 3.5 GeV/u,  initial =0.5  ∙mm∙mrad, (  p/p) = 1∙10 -3 electron beam: I e = 0.5 A, r e = 2 mm, T e|| = 5 meV;  = 0.024 (6 m/250 m)

23. 23 I.Meshkov, NICA Status MAC Video-Conference JINR, May 20, 2009 2. Heavy ions in NICA (Contnd) 2.2. Collider: electron cloud effect Electron cloud formation criteria The necessary condition: The sufficient condition (“multipactor effect”): Here  c is ion velocity, Z – ion charge number, b = 5 cm – vacuum chamber radius, r e – electron classic radius, l space – distance between bunches, m e – electron mass, c – the speed of light,  crit ~ 0.5 keV – electron energy sufficient for secondary electron generation. For NICA parameters ( 197 Au 79+ ions) (N bunch ) necessary ~ 7  10 8, (N bunch ) sufficient ~ 4  10 9.

24. 24 We began a common work with “Powder Metallurgy” Corporation (Minsk, Belorussia) on development of TiN coating technology for reduction of secondary emission from stainless steel vacuum chamber walls. I.Meshkov, NICA Status MAC Video-Conference JINR, May 20, 2009 2. Heavy ions in NICA (Contnd) What is “old” and what is new? 2.2. Collider: vacuum and electron clouds Electron cloud effect simulation with ECLOUD code [1] had shown the following: 1) e-clouds formation in straight section is negligible if b  5 cm, 2) dangerous part of the ring is vacuum chambers of dipoles (transverse magnetic field!); here secondary emission coefficient should be suppressed up to   1.3 [1] G. Rumolo, F. Zimmermann. CERN–SL–Note–2002–016 (AP)

25. 25 I.Meshkov, NICA Status MAC Video-Conference JINR, May 20, 2009 2. Heavy ions in NICA (Contnd) 2.2. Collider: the problems to be solved  Collider SC dipoles with max. B up to 4 T,  Lattice and working point “flexibility”,  RF parameters (related problem),  Single bunch stability,  Vacuum chamber impedance and multibunch stability,  Stochastic cooling of ion bunched beam,  Electron cooling at electron energy up to 2.5 MeV 6 m 3 m Collaboration with - All-Russian Institute for Electrotechnique (Moscow) - FZ Juelich - Budker INP

26. 26 I.Meshkov, NICA Status MAC Video-Conference JINR, May 20, 2009 3. Polarized particle beams in NICA Longitudinal polarization formation Upper ring MPD B SPD B Spin rotator: “Full Siberian snake”

27. 27 I.Meshkov, NICA Status MAC Video-Conference JINR, May 20, 2009 3. Polarized particle beams in NICA (Contnd) Longitudinal polarization formation SPD “Full Siberian snake” SPD B Lower ring “Siberian snake” : Protons, 1  E  12 GeV  (BL) solenoid  50 T∙m Deuterons, 1  E  5 GeV/u  (BL) solenoid  140 T∙m A problem: ring lattice in the strong solenoid field presence MPD

28. 28 From Nuclotron S Protons, 1  E  12 GeV  (BL) dipole  3 T∙m Deuterons, 1  E  5 GeV/u  (BL) dipole  5.8 T∙m I.Meshkov, NICA Status MAC Video-Conference JINR, May 20, 2009 3. Polarized particle beams in NICA (Contnd) Spin rotator B Polarized particle beams  injection   ~ 90 0

29. 29 Energy, GeV512 Proton number per bunch6E101.5E10 Rms relative momentum spread10E-3 Rms bunch length, m1.70.8 Rms (unnormalized) emittance,  mm  mrad0.240.027 Beta-function in the IP, m0.5 Lasslet tune shift0.00740.0033 Beam-beam parameter0.005 Number of bunches10 Luminosity, cm -2∙ s -1 1.1E30 I.Meshkov, NICA Status MAC Video-Conference JINR, May 20, 2009 3. Polarized particle beams in NICA (Contnd) Polarized proton beams parameters

30. 30 Thank you for your attention