Advancements in Rare Isotope Research at EURISOL Town Meeting
Cutting-edge research and facility developments in the field of rare isotopes were showcased at the EURISOL Town Meeting in INFN - Pisa. Topics included advances in EBIS charge breeders, the ARIEL Extension facility, and the CANREB laboratory with Electron Beam Ion Source technology. Various aspects of assembly and commissioning processes, as well as detailed studies on Radiative Recombination and Dielectronic Recombination, were also presented. These initiatives aim to enhance capabilities for isotope distribution, neutron-heavy isotopes, and efficient post-acceleration in the scientific community.
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Advances in EBIS charge breeders Michael A. Blessenohl
ARIEL Extension Advanced Rare IsotopE Laboratory New facility to expand capabilities of TRIUMF E-linac (photo-fission) Isotope distribution Neutron heavy isotopes More controlled Image source: TRIUMF Lab 21 August 2014 3 July 2018 EURISOL Town Meeting 2018, INFN - Pisa 1
CANREB Advanced Rare IsotopE Laboratory CANadian Rare-isotope facility with Electron Beam ion source Charge breeder and high resolution mass separator Efficient filtering Efficient post acceleration 3 July 2018 EURISOL Town Meeting 2018, INFN - Pisa 2
Electron Beam Ion Source (EBIS) 3 July 2018 EURISOL Town Meeting 2018, INFN - Pisa 3
Assembly (trap setup) 3 July 2018 EURISOL Town Meeting 2018, INFN - Pisa 4
Assembly (electron gun) 3 July 2018 EURISOL Town Meeting 2018, INFN - Pisa 5
Assembly (electron collector) 3 July 2018 EURISOL Town Meeting 2018, INFN - Pisa 6
Commissioning Commissioning 3 July 2018 EURISOL Town Meeting 2018, INFN - Pisa 7
Radiative Recombination (RR) Electron capture Photon Free electron Continuum 2p 2p L ?p= ?e+ ?c 3 2 1 2 2s K 1s 3 July 2018 EURISOL Town Meeting 2018, INFN - Pisa 8
?e= 5,5 keV ? = 4,5 T ?CDT = 2,5 kV Space charge 46 < q < 52 Image source: BSc thesis C. Warnecke 3 July 2018 EURISOL Town Meeting 2018, INFN - Pisa 9
Dielectronic Recombination (DR) Electron capture De-excitation Free electron Continuum 2p 2p L 3 2 Photon 1 2 2s ?p= ?? ?? K 1s 3 July 2018 EURISOL Town Meeting 2018, INFN - Pisa 10
Element: Ar ? = 6.0 T ?b = 64 mA Space charge revisited sp, tot = 47 eV 3 July 2018 EURISOL Town Meeting 2018, INFN - Pisa 11
Element: Ar ? = 6.0 T ?b = 64 mA Space charge compensation sp, e 200 eV ?e 75 m A ? 362 cm2 3 July 2018 EURISOL Town Meeting 2018, INFN - Pisa 12
Element: Ar ? = 6.0 T ?b = 125 mA Time evolution Trap capacity 5.7 109e Ar12+ 1.6 106 1.0 106 4.3 105 ms 3 July 2018 EURISOL Town Meeting 2018, INFN - Pisa 13
Conclusions Electron beam current of 1 A Current density in excess of 5000 A/cm Trap capacity of 1010elementary charges Outlook: Installation at beamline Tests at ARIEL facility Proposals for using an X-ray detector: On-line non-destructive characterization measurements demonstrated Using resonant processes for more efficient charge breeding 3 July 2018 EURISOL Town Meeting 2018, INFN - Pisa 14
The CANREB EBIS team 3 July 2018 EURISOL Town Meeting 2018, INFN - Pisa 15
Thank you for your attention. 3 July 2018 EURISOL Town Meeting 2018, INFN - Pisa 16
Challenges and Requirements 10 20 % in charge state distribution 100 Hz repetition rate Isotopes with lifetimes down to few ms 106ions/bunch, energy < 15 keV, long. length 1 s, 90 % acceptance Emittance energy < 14 keV ?, energy spread d? < 100 eV, bunch up to 1 ms. EPICS controls, compatible to TRIUMF control system ? ? 7 3 July 2018 EURISOL Town Meeting 2018, INFN - Pisa 17
Charge States 3 July 2018 EURISOL Town Meeting 2018, INFN - Pisa 18
Ionization Potentials 3 July 2018 EURISOL Town Meeting 2018, INFN - Pisa 19
Charge breeding of Cs 3 July 2018 EURISOL Town Meeting 2018, INFN - Pisa 20
Design of the CANREB EBIS Electron gun Radioactive ions 3 July 2018 EURISOL Town Meeting 2018, INFN - Pisa 21
Pierce emitter Cathode electrode Electron beam Cathode Anode 3 July 2018 EURISOL Town Meeting 2018, INFN - Pisa 22
Optical theory of e-beams Laminar model Brillouin flow Cathode as extended source Electrons emitted with transverse velocity of thermal distribution (Maxwellian) Uniform charge density No optical aberrations Optical model Herrmann theory Image source: G. Herrmann, Journal of Applied Physics 29, 127 (1958); http://dx.doi.org/10.1063/1.1723053 3 July 2018 EURISOL Town Meeting 2018, INFN - Pisa 23
Residual magnetic field 3 July 2018 EURISOL Town Meeting 2018, INFN - Pisa 24
Electron gun 0.25 emission surface Pierce-type emitter Improved coil design Ba dispenser cathode 612M Tungsten matrix Impregnation: Barium-calcium-aluminate BaO, CaO, Al2O3 Coating: 4000-6000 OsRu Adapted from Spectra-Mat, Inc. Image Source: Technical Bulletin 117, Spectra-Mat, Inc. 3 July 2018 EURISOL Town Meeting 2018, INFN - Pisa 25
Emission characteristics Child s Law: ? = 3 2 1 2 ? ?e ? ?2 9 ? Perveance: 3 2 ? = ?1 ? Image source: BSc thesis C. Warnecke 3 July 2018 EURISOL Town Meeting 2018, INFN - Pisa 26
Simulation 1. 2. 3. Electrostatics and Magnetostatics Electron Trajectory Calculation Integration of Ion Trajectories and Ionization Rate-Equations Charge breeding of Cs (mass 133 u) 3 July 2018 EURISOL Town Meeting 2018, INFN - Pisa 27
Major HV sections 3 July 2018 EURISOL Town Meeting 2018, INFN - Pisa 28
CAD model of the EBIS 3 July 2018 EURISOL Town Meeting 2018, INFN - Pisa 29
CAD model of the neutral gas injection system 3 July 2018 EURISOL Town Meeting 2018, INFN - Pisa 30
CAD model of the trap electrodes 3 July 2018 EURISOL Town Meeting 2018, INFN - Pisa 31
CAD model of the electron collector 3 July 2018 EURISOL Town Meeting 2018, INFN - Pisa 32
Simulation of ion trajectories 3 July 2018 EURISOL Town Meeting 2018, INFN - Pisa 33
Shift of DR resonances 3 July 2018 EURISOL Town Meeting 2018, INFN - Pisa 34
Extraction tests 3 July 2018 EURISOL Town Meeting 2018, INFN - Pisa 35
Element: Fe ? = 6.0 T ?b = 200 mA Injection and charge breeding tests 3 July 2018 EURISOL Town Meeting 2018, INFN - Pisa 36
Beam radius estimation Infinitely long electron beam of uniform charge density ?e: ?2? = ?e Solving for ?e: ?res= ? 0 ?e= 89.66 m ?res= ? ?e ?e= 54.38 m ?e 75 m ?0 1 ? ?? ?? ??? = ?e ? ?0 The solution for ? is: Using: ? ? 1 ?b 2 ?0= ?2 2+ ln?e 4??0 ? ?D+ ?0 2 1 , ? ?e 2 ?e ?D ?2 ?? = ? = ?0 1 ?e?02+ 1 ?D+ ?0ln 2, EURISOL Town Meeting 2018, INFN - Pisa ? ?e 3 July 2018 37 ?D
Current density estimation Using Herrmann theory to estimate ?c: Using: +?c2?c4 ?2?B4 1 4+8?e?B?c?c2 ?2?2?B4 1 2+ 2?e?b ??0 ???2 ?H= ?B ?B= ?c 3.282 mT 2 ?? ? = ?0 1 ?e?02+ 1 Using this result to calculate the beam radius at ?b= 1 A: ?H= 76.25 m The resulting current density is: 1 A ? 76.25 m2= 5474 A ? = cm2 3 July 2018 EURISOL Town Meeting 2018, INFN - Pisa 38