Transcript Слайд 1 - Nuclotron

Machine Advisory Committee Video-Conference
Concept and Status of The NICA Project
Nuclotron-based Ion Collider fAcility
I.Meshkov
for NICA Group
JINR, Dubna
May 20, 2009
1
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
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Introduction:
Development of the NICA Concept and TDR
January 2008
January 2009
Conceptual Design Report
of
Nuclotron-based Ion Collider fAcility
(NICA)
(Short version)
May 2009:
NICA TDR
&
MPD CDR
will be completed
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Introduction: Development of the NICA Concept
and Technical Design Report (Contnd)
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= 11027 cm-2s-1 (at sNN = 9 GeV/u)
1b) Light-Heavy ion colliding beams
2) Polarized beams of protons and deuterons:
pp sNN = 12  25 GeV (5  12.6 GeV kinetic energy )
dd sNN = 4  13.8 GeV (2  5.9 GeV/u ion kinetic energy )
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1. NICA scheme & layout
Synchrophasotron yoke
Spin Physics
Detector (SPD)
2.3 m
4.0 m
Booster
Nuclotron
MPD
Existing beam lines
(solid target exp-s)
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1. NICA scheme & layout (Contnd)
“Old” Linac LU-20
Booster
KRION + “New” HILAC
Nuclotron
Collider
SPD
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MPD
Beam dump
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2. Heavy ions in NICA
What is new?
2.1. Injector, Booster, Nuclotron
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have been replaced by Gold ions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
1) to avoid a big problem of “chemistry kitchen” with radioactive
Uranium oxides at ion sourсe, etc.;
2) to increase ion energy accelerated in the Booster
up to 608 MeV/u…
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2. Heavy ions in NICA (Contnd)
What is new?
2.1. Injector, Booster, Nuclotron
…this step allows us
3) …that increases ion stripping efficiency (after extraction from
the Booster and before injection into Nuclotron) up to 80% or more;
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”);
What is new:
5) the bunch compression: RF voltage jump for the bunch “overturn”
in phase space in Nuclotron will be replaced by RF phase jump.
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2. Heavy ions in NICA (Contnd)
What is new?
2.1. Injector, Booster, Nuclotron
Injector: 2×109 ions/pulse of 197Au32+
at energy of 6.2 MeV/u
Collider (45 Tm)
Storage of
17 (20) bunches  1109 ions per ring
at 14.5 GeV/u,
electron and/or stochastic cooling
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
Stripping (80%)
197Au32+

197Au79+
IP-1
Two
superconducting
collider rings
IP-2
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2х17 (20)
injection cycles
Nuclotron (45 Tm)
injection of one bunch
of 1.1×109 ions,
acceleration up to
14.5 GeV/u max.
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Bunch compression
Mayjump)
20, 2009
(RFJINR,
phase
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2. Heavy ions in NICA (Contnd)
2.1. Injector, Booster, Nuclotron
Bunch parameters dynamics in the injection chain
Stage
E
unnorm
p/p
lbunch
m
Intensity
loss,%
Space
charge
MeV/u
mmmrad
Injection (after
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
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
110-3
0.5
Loss = 40%
0.03
bunching on 4th
harmonics
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Q
0.0085
Nextr= 1E9
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2. Heavy ions in NICA (Contnd)
2.1. Injector, Booster, Nuclotron
Bunch compression in Nuclotron
Phase space portraits of the bunch
Bunch rotation by “RF amplitude jump” 15  120 kV
E – E0 , 2 GeV/div
2
1
, 10 deg./div
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2. Heavy ions in NICA (Contnd)
2.1. Injector, Booster, Nuclotron
Bunch compression in Nuclotron
Phase space portraits of the bunch (RF “phase jump”  = 1800)
E – E0 , 2 GeV/div
, 50 deg./div
E_r.m.c.
_r.m.s.
200 MeV/div.
5 deg./div.
(1 deg.  0.7 m)
_r.m.s.
0.5 eVsec/div
time, 0.1 sec/div.
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electron
cooling
1 (2-3) injection cycles,
electron cooling (?)
Arbitrary units
34 injection cycles to Collider rings
2. Heavy ions in NICA (Contnd)
of 1109 ions 197Au79+ per cycle
2.1. Injector, Booster, Nuclotron
1.71010 ions/ring
Time Table of The Storage Process
Booster magnetic field
Extraction, stripping to 197Au79+
0 0.5 1.5
3
4
t, [s]
Nuclotron magnetic field
Arbitrary units
bunch compression,
extraction
0 0.5 1.5
3
4
5
6
7
t, [s]
injection
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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.
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2. Heavy ions in NICA (Contnd)
2.2. Collider
What is new?
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.
V(t)
Cavity
voltage
(p)ion
Injection
Stack
time
Cooling’ is ON
Revolution period
The method was tested experimentally at ESR (GSI)
with electron cooling (2008).
NICA: Trevolution = 0.85  0.96 s, VBB  10 kV
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2. Heavy ions in NICA (Contnd)
2.2. Collider
General Parameters
Ring circumference, [m]
251.52
45.0
B max [ Tm ]
Ion kinetic energy (Au79+), [GeV/u]
Dipole field (max),
[ T ]
Quad gradient (max),
[ T/m ]
Number of dipoles / length
1.0  4.56
4.0
29.0
24 / 3.0 m
Number of vertical dipoles per ring
Number of quads / length
2 x 4
32 / 0.4 m
Long straight sections:
number / length
2 x 48.0 m
Short straight sections:
number / length,
4 x 8.8 m
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2. Heavy ions in NICA (Contnd)
2.2. Collider General parameters (Contnd)
βx_max / βy_max in FODO period, m
16.8 / 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)
Beam crossing angle at IP
Betatron tunes Qx / Qy
Chromaticity Q’x / Q’y
Transition energy, _tr / E_tr
RF system
Vacuum,
harmonics
amplitude, [kV]
[ pTorr ]
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9 m
0
5.26 / 5.17
-12.22 / -11.85
4.95 / 3.012 GeV/u
102
100
100  10
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2. Heavy ions in NICA (Contnd)
2.2. Collider General parameters (Contnd)
Resonance diagram
Working point
5.26 / 5.17
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2. Heavy ions in NICA (Contnd)
2.2. Collider General parameters (Contnd)
Collider beam parameters and luminosity
Energy, GeV/u
1.0
3.5
Ion number per bunch
1E9
1E9
17 (20)
17 (20)
3.8
0.25
1E-3
1E-3
0.3
0.3
0.75E26
1.1E27
0.056
0.047
0.0026
0.0051
650
50
Number of bunches per ring
Rms unnormalized beam emittance, ∙mm mrad
Rms momentum spread
Rms bunch length, m
Luminosity per one IP, cm-2∙s-1
Incoherent tune shift Qbet
Beam-beam parameter 
IBS growth time, s
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2. Heavy ions in NICA (Contnd)
2.2. Collider
BETACOOL
Alexander Smirnov
IBS Heating and cooling – bunch density evolution at electron cooling
Under cooling,
equilibrium with IBS
Gaussian distribution
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dN/dx, arb. units
dN/dx, arb. units
Before cooling
Nongaussian
distribution
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2. Heavy ions in NICA (Contnd)
2.2. Collider
IBS Heating and cooling – luminosity evolution at electron cooling
B [kG]
6E+276
8
Luminosity
5E+27
BETACOOL
simulation
[1E27 cm-24E+27
∙s-1] 4
6
3E+27
2E+272
4
1E+27
2
00
0
5
10
15
20
25
reference time, sec
T
= 10 eV
e
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)
Conclusion:
Electron magnetization
is much moreJINR,
preferable
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2. Heavy ions in NICA (Contnd)
2.2. Collider
IBS Heating and cooling – luminosity evolution at electron cooling
4
Luminosity
BETACOOL
B = 3 kG
simulation
[1E27 cm-2∙s-1]
2
0
Te = 10 eV
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)
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2. Heavy ions in NICA (Contnd)
2.2. Collider: electron cloud effect
Electron cloud formation criteria
b2
The necessary condition: ( N bunch )necessary   
,
Zre l space
2
The sufficient condition (“multipactor effect”):
( N bunch )sufficient 
b
Zre

 crit
2me c
2
.
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 ~ 7108,
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(Nbunch)sufficient ~ 4109.
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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)
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.
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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
3 m
Collaboration with
- All-Russian Institute for
Electrotechnique (Moscow)
- FZ Juelich
- Budker INP
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3. Polarized particle beams in NICA
Longitudinal polarization formation
MPD
Spin rotator:
“Full Siberian snake”
Upper ring
B
SPD
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3. Polarized particle beams in NICA (Contnd)
Longitudinal polarization formation
MPD
A problem: ring lattice in the
field presence
“Fullstrong
Siberiansolenoid
snake”
B
Lower ring
SPD
“Siberian snake”: Protons, 1  E  12 GeV  (BL)solenoid  50 T∙m
Deuterons,
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3. Polarized particle beams in NICA (Contnd)
Polarized particle beams  injection
S
 
( BL )dipole
B ion
B
 1   a 
~ 900
Protons, 1  E  12 GeV  (BL)dipole  3 T∙m
Deuterons, 1  E  5 GeV/u  (BL)dipole  5.8 T∙m
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3. Polarized particle beams in NICA (Contnd)
Polarized proton beams parameters
Energy, GeV
Proton number per bunch
Rms relative momentum spread
Rms bunch length, m
Rms
(unnormalized)
emittance, mmmrad
Beta-function in the IP, m
Lasslet tune shift
Beam-beam parameter
Number of bunches
Luminosity, cm-2∙s-1
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5
12
6E10
1.5E10
10E-3
10E-3
1.7
0.8
0.24
0.027
0.5
0.5
0.0074
0.0033
0.005
0.005
10
10
1.1E30 1.1E30
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For conclusion: NICA status and plans
2009
2010
2011
2012
2013
2014
2015
KRION
LINAC + trans. channel
Booster: magnetic system
Thank you for your attention
Booster + trans. channel
Nuclotron-M
Nuclotron-NICA
Transfer channel to Collider
Collider
Diagnostics
PS systems
Control systems
Infrastructure
R&D
design Manufctrng + mounting
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mountg+commssiong
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comms/operatn operation
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