Advances with Electron - PowerPoint Presentation

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Advances with Electron - PPT Presentation

cyclotron resonance charge breeder and prospects EURISOL TOWN MEETING Pisa July 24th 2018 1 T Thuillier J Angot LPSC R Vondrask ANL L Maunoury P Delahaye ID: 787557

ecris ecr plasma charge ecr ecris charge plasma ion background beam ghz rib clean amp peaks gas operation spes

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Slide1

Advances with Electron cyclotron resonance charge breeder - and prospects -

EURISOL TOWN MEETING, Pisa, July 2-4th 2018

T. Thuillier , J. Angot, LPSCR. Vondrask, ANLL. Maunoury, P. Delahaye, M. Dubois, GANILA. Galata, SPES, LNLF. Ames, TRIUMF

Slide2

Electron Cyclotron Resonance Ion Source Charge BreederA modified ECR Ion Source accepting

1+ ionsHot electrons, cold ions

Step by step ionization

Axial and Radial

Magnetic

field

ECR

Iso-B

lines

esonance

Magnetized

plasma

Follows

field

lines

Buffer

gas

Slide3

ECRIS CB Ion CaptureCoulomb collision→ thermalisation

→diffusion →capture

Potential

(V)

Low

dens

. Plasma

Te < 100 eV

ECR Zone

Potential

Dip

lectrostatic

(~1-10 V)

Ion confinement

Dense plasma

Te> 1

keV

Pure

Gas

Injection

, He,H

)

microwaves

ground

Slide4

ECR Charge Breeders in the World4

facility

ECR

CB typestatus CARIBU, Argonne, MI, USAA-ECRstoppedISAC, TRIUMF, CanadaPHOENIXUnder operationLPSC, France

PHOENIXUnder

operation, R&D

SPES, LNL,

ItalyPHOENIXUnder

operation

SPIRAL1,GANIL, France

PHOENIX

Under construction

Texas A&M,

College

station, TX, USA

A-ECR

Under

operation

TRIAC,

KEK- JAERI, JapanKEK-CBFacility closed

Slide5

Today ECRIS CB technologyBased on 20 years old 14 GHz ECRIS design

Vacuum~10

-7

down to 10-8 mbar (plastic o-rings, non bakeable)Material facing plasma : stainless steel, low carbon steel, aluminum alloy, copper…=> contamination (gas, condensable sputtering)5A ECR (ANL)

PHOENIX BOOSTER

(LPSC, GANIL, TRIUMF, SPES)

Slide6

Orders of MagnitudesSignal to Noise ratio

is a key parameter for ECRIS CB usage:

14 GHz ECR

Itotal~1 mA(~ Buffer gas~

Wall

sputtering

whole

ion

spectrum

within

1+ signal

+ signal

Contaminants within

Gases contaminants~

within

Signal (pps)

Signal/Noise0.010.11

10100

N+ RIB fraction0.9%9%50%91%99%Signal (pps)Signal/Noise0.010.1110100N+ RIB fraction0.9%9%50%91%99%For estimate

Slide7

Status of Today ECRIS CB ResearchPROS

Robust

CW operation1+

Intensity up to 1-10 pµA1+N+ Efficiency~4-25% CB time ~1-20 ms/charge stateLIMITSBeam contamination from the source walls~ 103 -104 pps background noiseA/Q~3 up to A=50A/Q~7 up to A=1507Performances are based on 20 years old ion source designsCAN ECRIS CB BE ENHANCED? YES!

Slide8

ECRIS CB efficiencies8

Slide9

Status of ECRIS CB In the world

Slide10

ECRIS CB at SPIRAL1 upgradeCollaboration with ANLCARIBU feedbak

experience used to modify

the SPIRAL1 PHOENIX Booster

Vacuum optimization Plug injection symétriqueAluminium walls2 RF portsCollaboration with LPSCExperimental commissioning tests at LPSCsuccessful10InjectionExtractionBooster

Slide11

GANIL-SPIRAL1 upgradeSPIRAL1 Facility restarted in March 2018P. Delahaye, L. Maunoury, M. Dubois et al.

3) post

acceleration CIME cyclotronNanogan3 TIS unmounted in the caveECR CB

1+ OR N+ TIS

FC13

FC81

FC11

1) RIB Production

1+ FEBIAD TIS

(condensables

)

N+ Nanogan3

(

gas

)

2) Charge state adaptation

PHOENIX ECR Charge Breeder

Slide12

SPIRAL1 upgrade: operation modes« Shooting Through » mode for gaseous

elements

Transport efficiencyLEBT(FC81/13)CIME (FC11/81)TotalBEFORE UPGRADE80%20%16%AFTER UPGRADE46%42%17%

ECR

N+

@26kV

FC13

FC81

FC11

@7.67MeV/A

1st RIB

produced

with

Nanogan3 TIS: 14O4+ECR CB OFF14O4+ send through itGlobal transmission efficiency keptCIME cyclotronM/M~1000

Slide13

SPIRAL1 upgrade: operation modes1+N+ Mode : Charge breeding in the ECR Ion SourceFirst beam: 37

K1+ charge bred to 37K

9+ with an efficiency of 5.3%

Preliminary (short test RUN)Measured on an ID station13Booster FEBIAD TIS

Identification

station

Slide14

SPIRAL1 upgrade: operation modesECR Charge greeder used as a standard ion s

ource to produce stable beam into

CIMESaving power to GANILFast energy

changeIndustrial applications and astrophysics14Stable Ion BeamRequirementBoosterE72536Ar @3.2MeV/A36Ar7+ @15kVEM9784Kr @2MeV/A84Kr @5MeV/A84Kr @7MeV/A84Kr11+@14,3kV84Kr17+ @21.5kV84Kr20+ @28.8kVEM97129Xe @2,5MeV/A129Xe @5MeV/A129Xe @7MeV/A129Xe22+ @13.3kV129Xe22+ @26.6kV129Xe27+ @32.7kV

ECR CB

Slide15

SPES ADIGE Injector15

Medium

Resolution Mass

SpectrometerM/ M~1000 (150 kV HV Platform) ECRIS CBStable 1+ SourceElectrostatic LEBTMagnetostatic LEBTPost accelerationUnder installation

Slide16

SPES ADIGE Injector

1+ stable beam test 09/2018Stable 1+N+ Test : 06/2019

Post acceleration1+ Source cage

Dipoles

Magnetic

triplets

Electrostatic

triplets

Successful FAT

Slide17

SPES:

Beam Purity R&D

First Action: R&D on reductions

of contaminantsAgreement LNL-LPSC under discussionTests on the LPSC test benchDesign, construction and test of 2 Aluminum plasma chambersAnalysis of contamination induced by SS and AlTest of hot and cold liners to mitigate the contaminant yieldNb, Ta or W17Hot linersCold linersplasma chamber

Slide18

SPES : Beam Purity IssuesPossible clean beams

available for post-accelerationAssuming

worst conditions of contaminationand separation

18POSSIBLE RIBs FOR POST-ACCELERATIONWITH CONVENTIONAL MATERIAL26AlContaminated by 13C, 26Mg, 52Cr, 78Kr: other materials for chamber94RbContaminated by 94Mo (SS)130SnPossible clean peaks at 19+,29+132SnPossible clean peaks at 19+,21+,23+132Sb

132

134

Possible clean peaks at 27+,31

138

Possible clean peaks at 20+,22+,23+,26+,28+,30+,31+

POSSIBLE RIBs FOR

POST-ACCELERATION

WITH LINERS R&D

Still problems

due to

C, 78Kr: to be checked after vacuum cleaning94RbPossible clean peaks at 15+,16+,21+130SnPossible clean peaks at 19+,22+,27+,29+,32+132SnPossible clean peaks at 19+-21+,23+-25+,30+-32+132Sb132Te134TePossible clean peaks at 22+,26+,27+,28+,33+138CsPossible clean peaks at 20+,22+-26+,28+,32+Beams of interest

R&D

LINERS SHOULD INCREASE CHARGE STATES AVAILABILITY

Slide19

Recent R&D at LPSCDone with the PHOENIX Booster on the 1+N+ test bench

Slide20

Plasma stability and background level

Plasma k

inetic instabilities transiently

generate a huge plasma potential Vp~1 kVStrong sputtering from the wall Peak identification shows: stainless steel plasma chamber composition: Fe, Cr, Mo, Ni, Al, Zn, Cu, MnElectrodes composition (Al alloy 2017): Al, Cu, Mn, ZnRelease of previous condensed 1+ beam (Cs,Rb,K)20stableunstableJoint study with JYFL & IAP RAS

Slide21

Magnetic confinement upgradeImproving axial magnetic field

trap had important effects

Axial magnetic field

profile: no plug: plugNew plugSoft iron

plug

High

efficiency

increase

For

low

masses

Higher

charge state

efficiency

With

rise

time

<10 ms/Q

Slide22

Short 1+ pulse StudyStudy transient plasma and possible 1+ ion accumulation effect

on the buffer gas plasma

The time to extract 90% of the N+ ions <

traditional CB time by ~10%No noticeable accumulation effect was observed221+N+Integral90%long 1+ pulse

Slide23

CARIBU ECRIS CB TestamentAfter an intensive research on background reduction

, the ECRIS CB was stopped at Argonne and replaced

by an EBISthe RIB signal (

pps)was lower than the ECRIS ion background and the mass resolution of the downstream accelerator () was not sufficient to reduce significantly the background<3% RIB content in the accelerated beam on the target 23ECRIS swampEBIS pool

Slide24

CARIBU ECRIS CB TestamentExample of 146Ba done

with the ECRIS2.7% of RIB content in the beam

with

100% RIB would need or RIB intensity increased by 2424

13+

18+

120

23+

136

26+

146Ba28+193Ir37+

198Hg38+

% of total beam current

198

38+68Zn13+146Ba26+197Ir36+120Sn23+94Mo18+

Slide25

CARIBU ECRIS TestamentMany techniques experimented to reduce the ECRIS beam background :

CO2 snow cleaningAluminum

coating

25Reduction factorCO2 cleaningAL coatingF20160Cl417Fe50Not detectableAr-22%3

Slide26

CARIBU ECRIS CB TestamentAtomic Layer DepositionCreating a thick conformal

homogeneous coatingBuit

atomic Layer by atomic layer An Al203 layer

could be deposited on all the parts located under vacuum26Atomic LayerDeposition (ALD)SlowCoats all sidesConformal

200 nm

ZnO

Slide27

Binary Reaction Sequence for Al2O3 1 ALD Cycle of TMA/H2

O Deposits 1 Al2O3 “Monolayer”

CH3

(CH

)

Trimethyl Aluminum

(TMA)

OAlCH3CH3CH3OHOH

Slide28

CARIBU ECRIS TestimonyNew ECR3 permanent magnet source is being installedPossibility to prototype ALD system for use with this sourceWill provide proof of principle with minimal disruption to operations

Slide29

TRIUMF ECRIS CBPHOENIX BOOSTER purchased from PantechnikU

nder operation at TRIACModified by TRIUMF

2 stage ion injection & extractionAl coating

29plasma chambermagnet yoke

Slide30

TRIUMF: A/Q selection with Nier type spectrometer30

ion optical simulation for mass resolution after charge state breeding

ΔM/M > 200

Slide31

LINAC chain used as mass filter31

Before final filtration

After final filtration

94Mo/Rb/Sr132Xe119Sn113In107Ag69Ga

94Mo/Rb/Sr

using LINAC chain as mass filter (M/

ΔM≈1000)additional stripping at 1.5 MeV/u to 94Rb

22+

laser ionized

Sr:

Sr:Rb

= 3:1

charge bred to

15+

1·10

ions/s (~1.5%)

accelerated and delivered

to TIGRESS experimentParticle ID from ΔE-E after acceleration(M. Marchetto et al. proceedings LINAC2012, JACoW.org)

Slide32

TRIUMF CB Results32

Results:

ECR charge state breeder at ISAC operational since 2008

isotopes from more than 15 elements have been charge bred so farrange of ions charge bred for acceleration: 21Na – 160Er Efficiency per charge state 1-5%problems: high background long breeding time (~20 ms*q)Outlook:improvements to ECR charge breeder → Joseph AdegunEBIS charge breeder → Brad Schultz158Er

Slide33

ECR CB Prospects

Slide34

Prospect: Improve the ion captureOptimize the capture with a denser and a longer

and plasmaToday, a part of the 1+ beam

is not captured, even

some 2+ and 3+ are ionized on flight and not captured (10-20% lost)34

10-20%

Non

captured

ions

Slide35

Prospect: Improve the ion capture

Lengthening the ECR plasma of the booster at 14 GHz from 14 cm to 40 cm would

grant a 99% 1+ captureAt higher

frequency (eg: 18 GHz) 25 cm plasma is necessary to capture all the 1+35unefficient1+ capture100%1+ captured

Slide36

Long ECRIS plasma already existsRIKEN SC ECRIS 18-28 GHz can generate

flat magnetic field

Slide37

Prospect: Reduce the CB timeECR frequency

scaling law : no limit

so far up to 28 GHz operationPlasm

a density : Charge Breeding Time: Today, standard ECR CB

are operated at

14 GHz

An 18 GHz ECR CBwould reduce

by -40%

GHz ECR

would

reduce

-75%

With

respect to 14GHz operation 37-40%-75%todayGreat time Reduction BUT it would increase the background from the wall as Only suitable for very high RIB intensity

Slide38

Prospect: Increase the mean N+ ion charge state

Optimize the magnetic confinement using

up to date know-howLarger plasma chamber

radius Demonstated with PHOENIX V2V3 upgrade (SPIRAL2)Larger plasma chamber lengthWith an optimized ECR CB:Xe42+ (A/Q~3 ; A=132)U42+ (A/Q~6 ; A=238) 38V2V3

Slide39

Prospect: Reduce ion contaminationGeometrical background reduction

by dilutionContaminant density

A 40 cm ECR plasma

length and 30 cm diameterwould reduce the background by a factor of 5 at 14 GHzUse a pure material for everything facing the plasmaMuch less background peakspossible bakeable materials : Titanum, Niobium, TantalumGet rid of gas contaminantFully Bakeable source, UHV technique H2 or He Gas injection purified with a cryo pumpIt is worth making a R&D on background reduction in ECRIS CB

Slide40

Prospect for EURISOL

Superconducting

ECR CB @

GHz

NbTi@4 K

plasma

chamber

pure

Ti or

Nb or Ta

Thermal