Advances in ECR Charge Breeders ADVANCES WITH ELECTRON
Advances in ECR Charge Breeders ADVANCES WITH ELECTRON CYCLOTRON RESONANCE CHARGE BREEDER - AND PROSPECTS T. Thuillier , J. Angot, LPSC R. Vondrask, ANL L. Maunoury, P. Delahaye, M. Dubois, GANIL A. Galata, SPES, LNL F. Ames, TRIUMF EURISOL TOWN MEETING, Pisa, July 2 -4 th 2018 EURISOL Town Meeting, Tuesday July 3 rd 2018 1
Advances in ECR Charge Breeders Electron Cyclotron Resonance Ion Source Charge Breeder Ø A modified ECR Ion Source accepting 1+ ions Buffer gas § Hot electrons, cold ions Ø Step by step ionization N+ 1+ Axial and Radial Magnetic field Bz RF BECR z RF Resonance Magnetized plasma Follows field lines N+ 1+ Iso-B lines EURISOL Town Meeting, Tuesday July 3 rd 2018 2
Advances in ECR Charge Breeders ECRIS CB Ion Capture Ø Coulomb collision→ thermalisation →diffusion →capture Pure Gas Injection (O 2, He, H 2) ground Dense plasma Te> 1 ke. V ECR Zone N+ 1+ Low dens. Plasma Te < 100 e. V Potential (V) HV microwaves ground Potential Dip Electrostatic (~1 -10 V) Ion confinement EURISOL Town Meeting, Tuesday July 3 rd 2018 3
Advances in ECR Charge Breeders in the World facility ECR CB type status A-ECR stopped ISAC, TRIUMF, Canada PHOENIX Under operation LPSC, France PHOENIX Under operation, R&D SPES, LNL, Italy PHOENIX Under operation SPIRAL 1, GANIL, France PHOENIX Under construction A-ECR Under operation KEK-CB Facility closed CARIBU, Argonne, MI, USA Texas A&M, College station, TX, USA TRIAC, KEK- JAERI, Japan EURISOL Town Meeting, Tuesday July 3 rd 2018 4
Advances in ECR Charge Breeders Today ECRIS CB technology Ø Based on 20 years old 14 GHz ECRIS design § PHOENIX BOOSTER (LPSC, GANIL, TRIUMF, SPES) § A ECR (ANL) § 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) EURISOL Town Meeting, Tuesday July 3 rd 2018 5
Advances in ECR Charge Breeders Orders of Magnitudes 14 GHz ECR N+ signal Ø Signal to Noise ratio is a key parameter for ECRIS CB usage: Signal (pps) Signal/Noise 0. 01 0. 1 1 10 100 N+ RIB fraction 0. 9% 9% 50% 91% 99% EURISOL Town Meeting, Tuesday July 3 rd 2018
Advances in ECR Charge Breeders Status of Today ECRIS CB Research PROS Ø Ø Ø LIMITS Robust CW operation 1+ Intensity up to 1 -10 pµA 1+ N+ Efficiency~4 -25% CB time ~1 -20 ms/charge state Ø Beam contamination from the source walls § ~ 103 -104 pps background noise Ø A/Q~3 up to A=50 Ø A/Q~7 up to A=150 Performances are based on 20 years old ion source designs CAN ECRIS CB BE ENHANCED? YES! EURISOL Town Meeting, Tuesday July 3 rd 2018 7
Advances in ECR Charge Breeders ECRIS CB efficiencies EURISOL Town Meeting, Tuesday July 3 rd 2018 8
Advances in ECR Charge Breeders Status of ECRIS CB In the world EURISOL Town Meeting, Tuesday July 3 rd 2018
Advances in ECR Charge Breeders ECRIS CB at SPIRAL 1 upgrade Ø Collaboration with ANL § CARIBU feedbak experience used to modify the SPIRAL 1 PHOENIX Booster • Vacuum optimization • Plug injection symétrique • Aluminium walls • 2 RF ports Ø Collaboration with LPSC § Experimental commissioning tests at LPSC § successful Injection Booster EURISOL Town Meeting, Tuesday July 3 rd 2018 Extraction 10
Advances in ECR Charge Breeders GANIL-SPIRAL 1 upgrade Ø SPIRAL 1 Facility restarted in March 2018 § P. Delahaye, L. Maunoury, M. Dubois et al. 1) RIB Production 1 N+ + OR TI S Ø 1+ FEBIAD TIS (condensables) Ø N+ Nanogan 3 (gas) EC R CB FC 81 FC 13 2) Charge state adaptation Ø PHOENIX ECR Charge Breeder FC 11 3) post acceleration Ø CIME cyclotron EURISOL Town Meeting, Tuesday July 3 rd 2018 Nanogan 3 TIS unmounted in the cave 11
Advances in ECR Charge Breeders SPIRAL 1 upgrade: operation modes Ø « Shooting Through » mode for gaseous elements EC N R + 14 O 4+@26 k. V FC 81 § 1 st RIB produced with Nanogan 3 TIS: 14 O 4+ § ECR CB OFF FC 13 § 14 O 4+ send through it § Global transmission efficiency kept 14 O 4+ @7. 67 Me. V/A FC 11 Transport efficiency LEBT (FC 81/13) CIME (FC 11/81) Total BEFORE UPGRADE 80% 20% 16% AFTER UPGRADE 46% 42% 17% EURISOL Town Meeting, Tuesday July 3 rd 2018 12
Advances in ECR Charge Breeders SPIRAL 1 upgrade: operation modes Ø 1+N+ Mode : Charge breeding in the ECR Ion Source FE B TI IAD S § First beam: 37 K 1+ charge bred to 37 K 9+ with an efficiency of 5. 3% § Preliminary (short test RUN) § Measured on an ID station Bo 37 K 9+ os te r 37 K 1+ Identification station EURISOL Town Meeting, Tuesday July 3 rd 2018 13
Advances in ECR Charge Breeders SPIRAL 1 upgrade: operation modes Ø ECR Charge greeder used as a standard ion source to produce stable beam into CIME § Saving power to GANIL § Fast energy change § Industrial applications and astrophysics Stable Ion Beam EC R CB E 725 EM 97 EURISOL Town Meeting, Tuesday July 3 rd 2018 Requirement 36 Ar @3. 2 Me. V/A Booster 36 Ar 7+ @15 k. V 84 Kr @2 Me. V/A 84 Kr @5 Me. V/A 84 Kr @7 Me. V/A 84 Kr 11+@14, 3 k. V 129 Xe 22+ @2, 5 Me. V/A 129 Xe @7 Me. V/A 84 Kr 17+ @21. 5 k. V 84 Kr 20+ @28. 8 k. V @13. 3 k. V 129 Xe 22+ @26. 6 k. V 129 Xe 27+ @32. 7 k. V 14
Advances in ECR Charge Breeders SPES ADIGE Injector Ø Under installation ECRIS CB Post acceleration Magnetostatic LEBT Stable 1+ Source Electrostatic LEBT EURISOL Town Meeting, Tuesday July 3 rd 2018 15
Advances in ECR Charge Breeders SPES ADIGE Injector Ø 1+ stable beam test 09/2018 Successful FAT Ø Stable 1+N+ Test : 06/2019 Magnetic triplets Electrostatic triplets Post acceleration 1+ Source cage Dipoles EURISOL Town Meeting, Tuesday July 3 rd 2018 16
Advances in ECR Charge Breeders SPES: Beam Purity R&D Ø First Action: R&D on reductions of contaminants § Agreement LNL-LPSC under discussion § Tests on the LPSC test bench Ø Design, construction and test of 2 Aluminum plasma chambers Ø Analysis of contamination induced by SS and Al Ø Test of hot and cold liners to mitigate the contaminant yield plasma chamber § Nb, Ta or W Hot liners EURISOL Town Meeting, Tuesday July 3 rd 2018 Cold liners 17
Advances in ECR Charge Breeders SPES : Beam Purity Issues Ø Possible clean beams available for post-acceleration § Assuming worst conditions of contamination and separation Beams of interest POSSIBLE RIBs FOR POST-ACCELERATION WITH LINERS R&D POSSIBLE RIBs FOR POST-ACCELERATION WITH CONVENTIONAL MATERIAL 26 Al Contaminated by 13 C, 26 Mg, 52 Cr, 78 Kr: other materials for chamber 94 Rb Contaminated by 94 Mo (SS) 130 Sn Possible clean peaks at 19+, 29+ 132 Sn 132 Sb Possible clean peaks at 19+, 21+, 23+ 132 Te 134 Te Possible clean peaks at 27+, 31+ 138 Cs Possible clean peaks at 20+, 22+, 23+, 26+, 28+, 30+, 31+ 26 Al 94 Rb R&D 130 Sn 132 Sb 132 Te 134 Te 138 Cs Still problems due to 13 C, 78 Kr: to be checked after vacuum cleaning Possible clean peaks at 15+, 16+, 21+ Possible clean peaks at 19+, 22+, 27+, 29+, 32+ Possible clean peaks at 19+-21+, 23+25+, 30+-32+ Possible clean peaks at 22+, 26+, 27+, 28+, 33+ Possible clean peaks at 20+, 22+-26+, 28+, 32+ LINERS SHOULD INCREASE CHARGE STATES AVAILABILITY EURISOL Town Meeting, Tuesday July 3 rd 2018 18
Advances in ECR Charge Breeders Recent R&D at LPSC Ø Done with the PHOENIX Booster on the 1+N+ test bench EURISOL Town Meeting, Tuesday July 3 rd 2018 19
Advances in ECR Charge Breeders Plasma stability and background level Ø Plasma kinetic instabilities transiently generate a huge plasma potentia § Vp~1 k. V § Strong sputtering from the wall Joint study with JYFL & IAP RAS stable unstable Ø Peak identification shows: § stainless steel plasma chamber composition: Fe, Cr, Mo, Ni, Al, Zn, Cu, Mn § Electrodes composition (Al alloy 2017): Al, Cu, Mn, Zn § Release of previous condensed 1+ beam (Cs, Rb, K) EURISOL Town Meeting, Tuesday July 3 rd 2018 20
Advances in ECR Charge Breeders Magnetic confinement upgrade Ø Improving axial magnetic field trap had important effects High efficiency increase For low masses New plug Soft iron plug Axial magnetic field profile : no plug : plug EURISOL Town Meeting, Tuesday July 3 rd 2018 Higher charge state 7% efficiency With rise time <10 ms/Q
Advances in ECR Charge Breeders Short 1+ pulse Study Ø Study transient plasma and possible 1+ ion accumulation effect on the buffer gas plasma 1+ N+ Integral 90% long 1+ pulse Ø The time to extract 90% of the N+ ions < traditional CB time by ~10% Ø No noticeable accumulation effect was observed EURISOL Town Meeting, Tuesday July 3 rd 2018 22
Advances in ECR Charge Breeders CARIBU ECRIS CB Testament Ø EBIS pool EURISOL Town Meeting, Tuesday July 3 rd 2018 ECRIS swamp 23
Advances in ECR Charge Breeders CARIBU ECRIS CB Testament Ø 3% of total beam current 94 Mo 18+ 94 Zr 18+ 47 Ti 9+ 68 Zn 13+ EURISOL Town Meeting, Tuesday July 3 rd 2018 120 Sn 23+ 68 Zn 13+ 94 Mo 18+ 197 Ir 36 + 120 Sn 23 + + 146 Ba 26 198 Hg 38 + 193 Ir 37+ 136 Xe 26+ 146 Ba 28+ 24 198 Hg 38+ 24
Advances in ECR Charge Breeders CARIBU ECRIS Testament Ø Many techniques experimented to reduce the ECRIS beam background : § CO 2 snow cleaning § Aluminum coating Reduction factor CO 2 cleaning AL coating F 20 160 Cl 4 17 Fe 50 Not detectable Ar -22% 3 EURISOL Town Meeting, Tuesday July 3 rd 2018 25
Advances in ECR Charge Breeders CARIBU ECRIS CB Testament Ø Atomic Layer Deposition Ø Creating a thick conformal homogeneous coating § Buit atomic Layer by atomic layer Atomic Layer Deposition (ALD) Ø An Al 203 layer could be deposited on all the parts located under vacuum Si EURISOL Town Meeting, Tuesday July 3 rd 2018 Zn. O • • • Slow Coats all sides Conformal 200 nm 26
Advances in ECR Charge Breeders Binary Reaction Sequence for Al 2 O 3 Trimethyl Aluminum (TMA) A) OH OH OH CH 3 Al CH 3 CH 4 CH 3 Al 3 CHAl Al CH CH 3 3 OH OH OH Al(CH 3)3 H 2 O B) CH CH 33 CH 3 Al Al CH 3 3 OH OH OH H 2 O CH 4 H 2 O OH CH 3 OH OH CH Al 3 CH 3 Al OH OH OH Ø 1 ALD Cycle of TMA/H 2 O Deposits 1 Al 2 O 3 “Monolayer” EURISOL Town Meeting, Tuesday July 3 rd 2018 27
Advances in ECR Charge Breeders CARIBU ECRIS Testimony Ø New ECR 3 permanent magnet source is being installed Ø Possibility to prototype ALD system for use with this source § Will provide proof of principle with minimal disruption to operations EURISOL Town Meeting, Tuesday July 3 rd 2018 28
Advances in ECR Charge Breeders TRIUMF ECRIS CB Ø PHOENIX BOOSTER purchased from Pantechnik Ø Under operation at TRIAC Ø Modified by TRIUMF § 2 stage ion injection & extraction § Al coating magnet yoke plasma chamber EURISOL Town Meeting, Tuesday July 3 rd 2018 29
Advances in ECR Charge Breeders TRIUMF: A/Q selection with Nier type spectrometer ion optical simulation for mass resolution after charge state breeding ΔM/M > 200 EURISOL Town Meeting, Tuesday July 3 rd 2018 30
Advances in ECR Charge Breeders LINAC chain used as mass filter using LINAC chain as mass filter (M/ΔM≈1000) additional stripping at 1. 5 Me. V/u to 94 Rb 22+ Before final filtration After final filtration 132 Xe 113 In 94 Mo/Rb/Sr 119 Sn 107 Ag 94 Mo/Rb/Sr laser ionized 94 Sr: Rb = 3: 1 charge bred to 94 Sr 15+ 1· 107 ions/s (~1. 5%) accelerated and delivered to TIGRESS experiment 69 Ga • Particle ID from ΔE-E after acceleration (M. Marchetto et al. proceedings LINAC 2012, JACo. W. org) EURISOL Town Meeting, Tuesday July 3 rd 2018 31
Advances in ECR Charge Breeders TRIUMF CB Results: • • ECR charge state breeder at ISAC operational since 2008 isotopes from more than 15 elements have been charge bred so far range of ions charge bred for acceleration: 21 Na – 160 Er Efficiency per charge state 1 -5% problems: high background long breeding time (~20 ms*q) 158 Er Outlook: improvements to ECR charge breeder → Joseph Adegun EBIS charge breeder → Brad Schultz EURISOL Town Meeting, Tuesday July 3 rd 2018 32
Advances in ECR Charge Breeders ECR CB Prospects EURISOL Town Meeting, Tuesday July 3 rd 2018
Advances in ECR Charge Breeders Prospect: Improve the ion capture Ø Optimize the capture with a denser and a longer and plasma § Today, a part of the 1+ beam is not captured, even some 2+ and 3+ are ionized on flight and not captured (10 -20% lost) 3+ 1+ 1+ 2+ 10 -20% Non captured ions EURISOL Town Meeting, Tuesday July 3 rd 2018 34
Advances in ECR Charge Breeders Prospect: Improve the ion capture Ø Lengthening the ECR plasma of the booster at 14 GHz from 14 cm to 40 cm would grant a 99% 1+ capture Ø At higher frequency (eg: 18 GHz) 25 cm plasma is necessary to capture all the 1+ 100% 1+ captured unefficient 1+ capture EURISOL Town Meeting, Tuesday July 3 rd 2018 35
Advances in ECR Charge Breeders Long ECRIS plasma already exists Ø RIKEN SC ECRIS 18 -28 GHz can generate flat magnetic field EURISOL Town Meeting, Tuesday July 3 rd 2018 36
Advances in ECR Charge Breeders Prospect: Reduce the CB time Ø today -40% -75% EURISOL Town Meeting, Tuesday July 3 rd 2018 37
Advances in ECR Charge Breeders Prospect: Increase the mean N+ ion charge state Ø Bz Br V 3 z EURISOL Town Meeting, Tuesday July 3 rd 2018 V 2 r 38
Advances in ECR Charge Breeders Prospect: Reduce ion contamination Ø EURISOL Town Meeting, Tuesday July 3 rd 2018 39
Advances in ECR Charge Breeders Prospect for EURISOL Superconducting plasma chamber ECR CB @ 14 GHz pure Ti or Nb or Ta Nb. Ti@4 K Heater wire to bake out The plasma chamber Online up to 300°C EURISOL Town Meeting, Tuesday July 3 rd 2018 Thermal screen And Water cooled 300°Surface HV insulator Plasma chamber Ø 300 mm L 1200 mm Long ECR Plasma
Advances in ECR Charge Breeders THANK YOU FOR YOUR ATTENTION EURISOL Town Meeting, Tuesday July 3 rd 2018
- Slides: 41