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MAMI and Beyond. Electron cooling for high-energy ion beams Igor N. Meshkov JINR, Dubna. Schloss Waldthausen , Mainz March 30 – April 3, 2009. I.Meshkov, HE e-coolers MAMI and Beyond Schloss Waldthausen 30 .03 – 3 .04, 2009. Contents

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MAMI and Beyond

  • Electron cooling for high-energy ion beams

  • Igor N. Meshkov

  • JINR, Dubna

Schloss Waldthausen, Mainz

March 30–April 3, 2009


I.Meshkov, HE e-coolers MAMI and BeyondSchloss Waldthausen30.03 –3.04, 2009

  • Contents

  • Physics of electron cooling and cooler parameters

  • Engineering problems of electrostatic HE electron coolers

  • 3. Project of electron cooler at COSY (Budker INP / FZJulich)

  • 4. NICA project at JINR

  • 5. Linac-based electron cooler

  • 6. “Coherent electron cooling”

  • Conclusion


 in Particle Rest Frame (Vi) initial  Ve

2) Regime of a pre-cooled ion beam 

 in PRF (Vi) initial  Ve

I.Meshkov, HE e-coolers MAMI and BeyondSchloss Waldthausen30.03 –3.04, 2009


Electron cooling time for two regimes

1) Stacking regime

transverse dimension

longitudinal dimension

2) Regime of cooled ion beam

Cooling time is defined byelectron beamparameters.

I.Meshkov, HE e-coolers MAMI and BeyondSchloss Waldthausen30.03 –3.04, 2009

  • Physics of Electron Cooling and Cooler Parameters

Cooling time is defined by ion beam parameters.


IBS Heating and cooling –

- competing processes in regime of cooled beam

IntraBeam Scattering (IBS)

EC in regime of cooled ion beam

Ni– ion number per bunch

I.Meshkov, HE e-coolers MAMI and BeyondSchloss Waldthausen30.03 –3.04, 2009

One needs to provide EC  IBS


BETACOOL

Alexander Smirnov

IBS Heating and cooling –

- bunch density evolution at electron cooling

Under cooling,

equilibrium with IBS

Before cooling

Gaussian distribution

Nongaussian

distribution

dN/dx, arb. units

dN/dx, arb. units

I.Meshkov, HE e-coolers MAMI and BeyondSchloss Waldthausen30.03 –3.04, 2009


BETACOOL

Alexander Smirnov

  • Physics of Electron Cooling and Cooler Parameters

Electron magnetization effect

Luminosity evolution at electron cooling: L(t)

B [kG]

8

6

4

2

6

Luminosity

[cm-2∙s-1] 4

2

0

6

Luminosity

[cm-2∙s-1] 4

2

0

6

Luminosity

[cm-2∙s-1] 4

2

0

6

Luminosity

[cm-2∙s-1] 4

2

0

B [kG]

6

4

2

B [kG]

4

2

B [kG]

2

I.Meshkov, HE e-coolers MAMI and BeyondSchloss Waldthausen30.03 –3.04, 2009

Te = 10 eV

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 1: Electron magnetization is much more preferable


IBS Heating and cooling –

- competing processes in regime of cooled beam

Conclusion 2:

Both IBS and EC rates decrease with ion energy

as 45 if… x, y, p/p, Je, F… are the same. That

is a promising fact.

I.Meshkov, HE e-coolers MAMI and BeyondSchloss Waldthausen30.03 –3.04, 2009

However, all this makes the task of collider

luminosity achievement and preservation rather

complicated.


2. Engineering problems of electrostatic HE e-coolers

What experience do we have?

}

Our

“reference

points”

I.Meshkov, HE e-coolers MAMI and BeyondSchloss Waldthausen30.03 –3.04, 2009

Electrostatic accelerators and tandems,

Electron cooler prototype at Budker INP (1986):

1 MeV x 1 A, several hours continuous operation,

Electron cooler of 4.34 MeV at Fermilab.


2. Engineering problems of electrostatic HE electron coolers

Success at Tevatron

Collider Peak Luminosity (Run II)

4

3

2

1

0

Luminosity, 10E+32 cm-2s-1

  • 2002 2003 2004 2005 2006 2007 2008 2009 

  • Years

I.Meshkov, HE e-coolers MAMI and BeyondSchloss Waldthausen30.03 –3.04, 2009

Mainly owing to application of electron cooler at Recycler!

All Tevatron data  Alexandr Schemyakin and Sergei Nagaitsev (Fermilab)

Private communication, March 2009


coolers

See A.Jankowiak talk as well

I.Meshkov, HE e-coolers MAMI and BeyondSchloss Waldthausen30.03 –3.04, 2009

2. Engineering problems of electrostatic HE electron coolers

What do we plan to construct?

Electron coolers of

2 MeV at COSY (Budker INP / FZ Jülich)

2 MeV at COSY (Uppsala Univ./ FZ Jülich)

2.5 MeV at NICA (JINR, Dubna)

8.2 MeV at HESR, pp-bar mode (FAIR)

8.2 MeV at HESR, ep mode (FAIR)

54 MeV at RHIC (ii mode, ei mode)

See T.Roser talk as well


I.Meshkov, HE e-coolers coolersMAMI and BeyondSchloss Waldthausen30.03 –3.04, 2009

2. Engineering problems of electrostatic HE electron coolers

The problems:

2.1. High voltage performance

2.2. Limiting performance of accelerator tubes

2.3. High voltage generators

2.4. Power transmission to accelerator “head”

2.5. Electron current and HV stability

2.6. Electron beam formation, transportation

and recovering


2. Engineering problems of electrostatic HE electron coolers

2.1. High voltage performance

I.Meshkov, HE e-coolers MAMI and BeyondSchloss Waldthausen30.03 –3.04, 2009

SF6

Fermilab experience:

4.4 MV / 80 cm gap

E_Opertn = 55 kV/cm at

p/p_norm = 6

Conclusion 3:

In HE electron coolers

E_Opertn ~ 5.5 MV/m Electric strength of SF6 gas!


2. Engineering problems of electrostatic HE electron coolers

2.2. Limiting performance of accelerator tubes

Tandem experience: 1.7 – 2 MV/m

But! Small current of accelerated beam  10 A ions

Fermilab experience:1.2 MV/m at electron current

of accelerated beam (recuperation regime):

0.5 A – tested

0.1 A – operation, 2007-2009

I.Meshkov, HE e-coolers MAMI and BeyondSchloss Waldthausen30.03 –3.04, 2009

Conclusion 4:

HE Electron cooler size is defined mainly by

accelerator tube size!


2. Engineering problems of electrostatic HE electron coolers

2.3. High voltage generators

Existing options (by voltage increase):

1. “Dynamic machines”

1.1. Cockroft-Walton accelerator – up to 1 MV (practically)

1.2. “Electron-beam Ventil” (ELV, BINP) – a sophisticated version of

insulating core transformer  2 MV

1.3. Dynamitron ~ 4 MV max

I.Meshkov, HE e-coolers MAMI and BeyondSchloss Waldthausen30.03 –3.04, 2009

2. Electrostatic machines

2.1. Van de Graaff accelerators

2.2.Pelletron modification

“The record-holder” of DC accelerators: Vivitron (Univ. Louis Pasteur,

Strasbourg)  35 MV project, 25 MV operation.


I.Meshkov, HE e-coolers coolersMAMI and BeyondSchloss Waldthausen30.03 –3.04, 2009

2. Engineering problems of electrostatic HE electron coolers

2.4. Power transmission to accelerator “head”

One needs to place in an electron cooler “head”

a few power supplies:

1) Gun cathode filament PS: V ~ 15 V, P  300 W,

2) Gun control electrode PS: V  20 kV, P  2 W,

3) Collector suppressor electrode PS: V  2 kV, P  2 W,

4) Collector receiver PS: V  2 kV, P  3 kW.

  • Two options of power transmission:

  • Insulating core transformer – preferable, but  3-4 MV

  • Rotating rods  complicated, however  up to 25 MV (Vivitron)


I.Meshkov, HE e-coolers coolersMAMI and BeyondSchloss Waldthausen30.03 –3.04, 2009

2. Engineering problems of electrostatic HE electron coolers

2.5. Electron current and HV stability

Peculiarity of electron coolers: high reactive power (RP) of electron

beam at very low active power (AP) consumption.

This is especially well manifested in HE electron coolers.

Fermilab experience: RP = 4.34 MV x 0.1 A = 434 kW,

AP = 4.34 MV x 1.5 A  7 W,

HV stability  V/V  1∙10E-4


Voltage divider coolers

HV generator in “Dynamic machines”

Measuring

devise

Capacitive PU electrode

Voltage

regulator

Generating voltmeter

(J.C.Maxwell’s invention!)

Corona control in electrostatic machines

I.Meshkov, HE e-coolers MAMI and BeyondSchloss Waldthausen30.03 –3.04, 2009

2. Engineering problems of electrostatic HE electron coolers

2.5.Electron current and HV stability (Contnd)

HV stability is connected with electron beam losses.

HV stabilization methods: a few feed back loops consisting of

Measuring devices and voltage regulators:


2. Engineering problems of electrostatic HE electron coolers

2.6. Electron beam formation, transportation

and energy recovering

To magnetize or not – that is a question!

I.Meshkov, HE e-coolers MAMI and BeyondSchloss Waldthausen30.03 –3.04, 2009

Fermilab experience: Nonmagnetized electron cooling

Experience of low and middle energy electron coolers

and

Numerical simulations at high energy 

 magnetization is preferable


3. coolersProject of electron cooler at COSY (BINP/FZJ)

V.Parkhomchuk, Report at BINP-JINR-FZJ meeting at Budker INP

Novosibirsk, March 17-18, 2009

Main distinguishing characteristics of this HE electron cooler:1. Fast cooling: not hours but minutes  owing to much higher electron beam density – by 50-100 times2. Wide energy range – 24 keV  2 MeV3. Cooling of multicharge ions  recombination suppression by increase of electron transverse temperature Solution: electron magnetization and electron beam compression in the cooling sectionby magnetic field increase from 50-100 G on the gun cathode up to 2.5 – 5.0 kG in the cooling section !

I.Meshkov, HE e-coolers MAMI and BeyondSchloss Waldthausen30.03 –3.04, 2009


3. coolersProject of electron cooler at COSY (V.Parkhomchuk et al., contnd)

HV section of COSY cooler

Compressed gas release tubes

Turbine

Magn. field coils

Accelrtng tube

Decelertng tube

HV PS

30 kV

Compressed gas admission tubes

Control

electronics

I.Meshkov, HE e-coolers MAMI and BeyondSchloss Waldthausen30.03 –3.04, 2009


3. coolersProject of electron cooler at COSY (V.Parkhomchuk et al., contnd)

Gas Turbine and Generator Coil

I.Meshkov, HE e-coolers MAMI and BeyondSchloss Waldthausen30.03 –3.04, 2009


3. coolersProject of electron cooler at COSY (V.Parkhomchuk et al., contnd)

Electron Cooler for COSY (BINP/FZJ)

I.Meshkov, HE e-coolers MAMI and BeyondSchloss Waldthausen30.03 –3.04, 2009


3. coolersProject of electron cooler at COSY (D.Reistad et al.)

Electron Cooler for COSY (Uppsala Univ./FZJ)

Pelletron-based concept

Magnetized electron beam

I.Meshkov, HE e-coolers MAMI and BeyondSchloss Waldthausen30.03 –3.04, 2009


4. coolersNICA project at JINR

Project

of

Nuclotron-based Ion Collider fAcility (NICA)

and MultiPurpose Detector (MPD)

at JINR

Scientific case:

1. Study of exited nuclear matter in NN, pN and pp interactions

and search for the mixed phase of strongly interacting matter

in energy range of √s = 4  11 GeV/u

i.e. 197Au x 197Au in the kinetic energy range of 1 ÷ 4.5 GeV/u

at average luminosity (at 3.5 GeV/u)

Laverage = 110E+27 cm-2s-1

2. Study of spin physics in pp and dd collisions in energy

range of √s = 10  27 GeV/u (pp) and 4  13 GeV/u (dd)

Laverage 110E+30 cm-2s-1

I.Meshkov, HE e-coolers MAMI and BeyondSchloss Waldthausen30.03 –3.04, 2009


4. coolersNICA project at JINR (Contind)

Search for the mixed phase

of strongly interacting matter

1 fm/c ~ 3∙10-24 s

Elabs GeV/u

5 3.60

10 4.73

30 7.75

8012.42 RHIC (?)

158 17.36 NA49/61 (SPS)

NICA & CBM

Barionic chemical potential  [MeV]

I.Meshkov, HE e-coolers MAMI and BeyondSchloss Waldthausen30.03 –3.04, 2009


4. coolersNICA project at JINR (Contind)

NICA/ MPD Concept

January 2008

Conceptual Design Report

in progress,

to be completed 2009

Technical Design Report

in progress,

to be completed May 2009

I.Meshkov, HE e-coolers MAMI and BeyondSchloss Waldthausen30.03 –3.04, 2009


4. coolersNICA project at JINR (Contind)

Booster

Krion & Linac

Nuclotron

Collider

C = 251.2 m

MPD

Spin Physics Detector (SPD)

I.Meshkov, HE e-coolers MAMI and BeyondSchloss Waldthausen30.03 –3.04, 2009

NICA Scheme

Existing beam lines

(solid target exp-s)

Bldng 205


4. coolersNICA project at JINR (Contind)

Vladimir I.

Veksler

2.3 m

4.0 m

I.Meshkov, HE e-coolers MAMI and BeyondSchloss Waldthausen30.03 –3.04, 2009

Dismounting is in progress presently


4. coolersNICAproject at JINR (Contind)

I.Meshkov, HE e-coolers MAMI and BeyondSchloss Waldthausen30.03 –3.04, 2009

Collider General Parameters


4. coolersNICA project at JINR (Contind)

Beam dump

RF

MPD

RF

Spin rotator

Spin rotator

PU

PU

Kicker

Kicker

SPD

Beam dump

I.Meshkov, HE e-coolers MAMI and BeyondSchloss Waldthausen30.03 –3.04, 2009

Collider Structure

Injection channels


4. coolersNICA project at JINR (Contind)

I.Meshkov, HE e-coolers MAMI and BeyondSchloss Waldthausen30.03 –3.04, 2009

Collider beam parameters and luminosity


4. coolersNICA project at JINR (Contind)

“Twin magnets” for NICA collider rings

“Twin” quadrupoles

“Twin” dipoles (4.5 T)

I.Meshkov, HE e-coolers MAMI and BeyondSchloss Waldthausen30.03 –3.04, 2009


4. coolersNICA project at JINR (Contind)

I.Meshkov, HE e-coolers MAMI and BeyondSchloss Waldthausen30.03 –3.04, 2009

Polarized proton beams in NICA


4. coolersNICA project at JINR (Contind)

Longitudinally polarized beams in NICA

Yu.Filatov, 2009

Spin rotator

“full snake”

B

B

SPD

SPD

I.Meshkov, HE e-coolers MAMI and BeyondSchloss Waldthausen30.03 –3.04, 2009


4. coolersNICA project at JINR (Contind)

Longitudinally polarized beams in NICA (Contnd)

Spin rotator

“full snake”

B

B

B

SPD

SPD

I.Meshkov, HE e-coolers MAMI and BeyondSchloss Waldthausen30.03 –3.04, 2009


4. coolersNICA project at JINR (Contind)

2.5 MeV x 0.5 (1.0?) A

SC solenoid 0.2  1.0 T

The electron cooler for NICA collider

Electron beam 2:Recuperater

Electron beam 2:Accelerator

HV cascade generator(“Dynamitron”

Electron beam 1:Accelerator

Electron beam 1:Recuperater

Ion beam 1Ion beam 2

Toroidal solenoids

Straight and thin toroidal solenoids

I.Meshkov, HE e-coolers MAMI and BeyondSchloss Waldthausen30.03 –3.04, 2009


See T.Roser talk as well coolers

5. Linac-based electron cooler

Project of electron cooler for RHIC (BNL-Budker INP-JINR)

ions

e-gun

ions

electrons

Linac 2

Linac 1

electrons

Linac 3

Beam dump

ions

Bunch compressor

Linac 4

Bunch stretcher

I.Meshkov, HE e-coolers MAMI and BeyondSchloss Waldthausen30.03 –3.04, 2009


5. coolersLinac-based electron cooler (Contnd)

FEL MARS  Project at Budker INP

(Multipass Accelerator-Recuperator Source)

Energy Recovering Linac (ERL)

2 stages  8 + 12 MeV

andFEL of  = 50 mcm

Electron bunch parameters:

Parameters:

1st stage 2nd stage

Bunch charge, nC 1  1.5

Bunch duration, cm 2.0 0.6

Peak current, A 16 50

Norm. emittance, ∙mm∙mrad 30

p/p 1∙10E-3

Injection/recuperation energy 1.5 MeV

Average current, mA 30 10

ERL

FEL

Injector

I.Meshkov, HE e-coolers MAMI and BeyondSchloss Waldthausen30.03 –3.04, 2009

*)

*) Nikolai Vinokurov (Budker INP), private communication, March 2009


6. “Coherent electron cooling” coolers*)

See T.Roser talk as well

First idea: Yaroslav Derbenev, Proc. 7th All-Soviet Acc. Conf., v. 1, p. 269

Recent development:

Ya. Derbenev (JNL), Vl.Litvinenko (BNL), PRL 102, 114801 (2009)

1 2 3 4 5 6 7

Scheme of “The coherent electron cooler” (courtesy of Vl.Litvinenko, March 2009) :

1) Junction of ions and electrons, 2)Excitation of of electron beam bunching by ions (“plasma oscillation”) when traveling together, 3) Separation of ions and electrons, 4) Amplification of e-beam bunching when passing the undulator and separation of fast and slow ions in dispersion section, 5) Junction of ions and electrons, 6) Damping of ion momentum spread (kicker), 7) Separation of ions and electrons.

I.Meshkov, HE e-coolers MAMI and BeyondSchloss Waldthausen30.03 –3.04, 2009

*) Vladimir Litvinenko (BNL) courtesy, March 2009


Thank you for your attention! coolers

I.Meshkov, HE e-coolers MAMI and BeyondSchloss Waldthausen30.03 –3.04, 2009

Conclusion

  • Electron cooling method was successfully developed and applied to high energy antiprotons up to 8 GeV (4.34 MeV electron energy);

2.There are a few projects of HE electron coolers for ion

energy range 2  8 MeV/u based on electrostatic acceleration

that is adequate to this energy range;

3. An advance into higher energy range should be accomplished

by development of novel ideas.


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