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

1

Machine Advisory Committee Video-Conference

JINR, DubnaMay 20, 2009

Concept and Status of The NICAConcept and Status of The NICA ProjectProjectNNuclotron-baseduclotron-based I Ionon CColliderollider ffAAcilitycility

I.MeshkovI.Meshkovforfor NICA GroupNICA Group

2

ContentsIntroduction: 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

May 2009: NICA TDR

&MPD CDR

will be completed


January 2008

Conceptual Design Reportof

Nuclotron-based Ion Collider fAcility (NICA)(Short version)

January 2009

Introduction:

Development of the NICA Concept and TDR

4 I.Meshkov, NICA Status MAC Video-Conference JINR, May 20, 2009

The Project goals formulated in CDR remain:

1a) Heavy ion colliding beams 197Au79+ x 197Au79+ at

sNN = 4 11 GeV (1 4.5 GeV/u ion kinetic energy )

and

Laverage= 11027 cm-2s-1 (at sNN = 9 GeV/u)

1b) Light-Heavy ion colliding beams

2) Polarized beams of protons and deuterons:

pp sNN = 12 25 GeV (5 12.6 GeV kinetic energy )

dd sNN = 4 13.8 GeV (2 5.9 GeV/u ion kinetic energy )

Introduction: Development of the NICA Concept

and Technical Design Report (Contnd)


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

1. NICA scheme & layout

(Contnd)


“Old” Linac LU-20

KRION + “New” HILACBooster

Nuclotron

Collider MPD

SPD Beam dump

7

1) to avoid a big problem of “chemistry kitchen” with

radioactive Uranium oxides at ion sourсe, etc.;


2. Heavy ions in

NICAWhat is new?

The injection chain remains the same :

Injector Booster Nuclotron

But! Uranium ions 238U32+ to be generated with KRION

source

have been replaced by Gold ions 197Au32+.

This step allows us


2) to increase ion energy accelerated in the Booster

up to 608 MeV/u…

8

3) …that increases ion stripping efficiency (after extraction

from the Booster and before injection into Nuclotron) up to

80% or more;


What is new?


…this step allows us


(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”);


2.1. Injector, Booster,

Nuclotron


(Contnd)What is new?

Booster (25 Tm)1(2-3) single-turn

injection, storage of 2 (4-6)×109,acceleration up to 100

MeV/u,electron cooling,

acceleration up to 608 MeV/u

Nuclotron (45 Tm)injection of one

bunch of 1.1×109 ions,

acceleration up to 14.5 GeV/u max.

Collider (45 Tm)Storage of

17 (20) bunches 1109 ions per ring

at 14.5 GeV/u,electron and/or stochastic cooling

Stripping (80%) 197Au32+ 197Au79+

2х17 (20) injection

cycles

Injector: 2×109 ions/pulse of 197Au32+ at energy of 6.2 MeV/u

IP-1

IP-2

Two superconducting

collider rings

Bunch compression (RF phase jump)



(Contnd)

Bunch parameters dynamics in the injection

chain


Stage E MeV/u

unnorm mmmr

ad

p/p lbunch m

Intensityloss,%

Space charge

Q

Injection (after bunching on 4th harmonics

6.2 10 1.3E-3 6 10 0.022

After cooling (h=1)

100 2.45 3.8E-4 7.17 <10 0.016

At extraction 608 0.89 3.2E-4 3.1 0.0085

Injection (after stripping)

594 0.89 3.4E-4 3.1 <20 0.051

After acceleration 3500 0.25 1.5E-4 2 <1 0.0075

At extraction 3500 0.25 110-3 0.5 Loss = 40%

Nextr= 1E9

0.03



(Contnd)

Bunch compression in Nuclotron


Phase space portraits of the bunch

Bunch rotation by “RF amplitude jump” 15 120 kV

, 10 deg./div

E – E0 , 2 GeV/div

1 2



(Contnd)Bunch compression in 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 eVsec/div

E – E0 , 2 GeV/div

Phase space portraits of the bunch (RF “phase jump” = 1800)

, 50 deg./div



(Contnd) 2.1. Injector, Booster, NuclotronTime Table of The Storage

Process

0 0.5 1.5 3 4 t, [s]

1 (2-3) injection cycles,electron cooling (?)

electroncooling

0 0.5 1.5 3 4 5 6 7 t, [s]

Nuclotron magnetic field

Arb

itra

ry u

nit

sA

rbit

rary

un

its

injection

bunch compression,extraction

Extraction, stripping to 197Au79+

Booster magnetic field

34 injection cycles to Collider ringsof 1109 ions 197Au79+ per cycle

1.71010 ions/ring




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.




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)

StackInjection time

Cooling’ is ON

Cavity

voltage

(p)io

n

The method was tested experimentally at ESR (GSI)

with electron cooling (2008). NICA: Trevolution = 0.85 0.96 s, VBB 10 kV

16

Ring circumference, [m] 251.52

B max [ Tm ] 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 / length 24 / 3.0 m

Number of vertical dipoles per ring 2 x 4

Number of quads / length 32 / 0.4 m

Long straight sections: number / length

2 x 48.0 m

Short straight sections: number / length,

4 x 8.8 m



(Contnd) 2.2. Collider

General Parameters



(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, m

5.9 / 0.2

βx_min / βy_min in IP, m 0.5 / 0.5

Dx / Dy in IP, m 0.0 / 0.0

Free space at IP (for detector) 9 m

Beam crossing angle at IP 0

Betatron tunes Qx / Qy 5.26 / 5.17

Chromaticity Q’x / Q’y -12.22 / -11.85

Transition energy, _tr / E_tr 4.95 / 3.012 GeV/u

RF system harmonics amplitude, [kV]

102 100

Vacuum, [ pTorr ] 100 10

18


(Contnd)2.2. Collider General parameters (Contnd)

Resonance diagram


Working point5.26 / 5.17

19

Energy, GeV/u 1.0 3.5

Ion number per bunch 1E9 1E9

Number of bunches per ring 17 (20) 17 (20)

Rms unnormalized beam emittance, ∙mm mrad

3.8 0.25

Rms momentum spread 1E-3 1E-3

Rms bunch length, m 0.3 0.3

Luminosity per one IP, cm-2∙s-1 0.75E26 1.1E27Incoherent tune shift Qbet 0.056 0.047

Beam-beam parameter 0.0026 0.0051

IBS growth time, s 650 50



(Contnd)2.2. Collider General parameters (Contnd)

Collider beam parameters and luminosity

20

dN

/dx,

arb

. u

nit

s

Under cooling,

equilibrium with IBS

Nongaussian

distribution



(Contnd) 2.2. Colliderd

N/d

x, a

rb.

un

its

Before cooling

Gaussian distribution

IBS Heating and cooling – bunch density evolution at electron cooling

BETACOOL

Alexander Smirnov

21

Te = 10 eV



(Contnd)2.2. Collider

BETACOOL

simulation

Parameters

ion beam: 197Au79+ at 3.5 GeV/u, initial =0.5 ∙mm∙mrad, (p/p) = 1∙10-3

electron beam: Ie = 0.5 A, re = 2 mm, Te|| = 5 meV; = 0.024 (6 m/250 m)

IBS Heating and cooling – luminosity evolution at electron cooling

B [kG]

8

6

4

20

1E+27

2E+27

3E+27

4E+27

5E+27

6E+27

0 5 10 15 20 25reference time, sec

6

Luminosity

[1E27 cm-2∙s-1] 4

2

0

Conclusion: Electron magnetization is much more preferable



(Contnd) 2.2. Collider

IBS Heating and cooling – luminosity evolution at electron cooling

Te = 10 eV

BETACOOL

simulationB = 3 kG

4

Luminosity

[1E27 cm-2∙s-1]

2

0

Parameters (as on previous slide): ion beam: 197Au79+ at 3.5 GeV/u, initial =0.5 ∙mm∙mrad, (p/p) = 1∙10-3

electron beam: Ie = 0.5 A, re = 2 mm, Te|| = 5 meV; = 0.024 (6 m/250 m)



(Contnd)2.2. Collider: electron cloud effect

Electron cloud formation criteria

The necessary condition:

The sufficient condition (“multipactor effect”):

,lZr

b)N(

spacee

22

necessarybunch

Here c is ion velocity, Z – ion charge number,

b = 5 cm – vacuum chamber radius,

re – electron classic radius, lspace – distance between bunches,

me – electron mass, c – the speed of light,

crit ~ 0.5 keV – electron energy sufficient for secondary electron generation.

For NICA parameters (197Au79+ ions)

(Nbunch)necessary ~ 7108, (Nbunch)sufficient ~ 4109.

.cm2Zr

b)N(

2e

crit

esufficientbunch

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.



(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)



(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


3. Polarized particle beams in

NICA Longitudinal polarization

formation

Upper ring

MPD

B

SPD

B

Spin rotator:

“Full Siberian snake”



(Contnd)Longitudinal polarization

formation

SPD

“Full Siberian snake”

SPD

BLower 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

From NuclotronS

Protons, 1 E 12 GeV (BL)dipole 3 T∙m

Deuterons, 1 E 5 GeV/u (BL)dipole 5.8 T∙m

a1B

)BL(

ion

dipole



(Contnd)

Spin rotator

B

Polarized particle beams injection

~ 900

29

Energy, GeV 5 12

Proton number per bunch 6E10 1.5E10

Rms relative momentum spread 10E-3 10E-3

Rms bunch length, m 1.7 0.8

Rms (unnormalized) emittance, mmmrad

0.24 0.027

Beta-function in the IP, m 0.5 0.5

Lasslet tune shift 0.0074 0.0033

Beam-beam parameter 0.005 0.005

Number of bunches 10 10

Luminosity, cm-2∙s-1 1.1E30

1.1E30



(Contnd)

Polarized proton beams parameters

30

Infrastructure

Control systems

PS systems

Diagnostics

Collider

Transfer channel to Collider

Nuclotron-NICA

Nuclotron-M

Booster + trans. channel

LINAC + trans. channel

KRION

2015201420132012201120102009

operation

comms/operatn

mountg+commssiong

Manufctrng + mounting

design

R & D


For conclusion: NICA status and plans

Booster: magnetic system Thank you for your attention

Documents

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