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A new prototype of super buncher for RI ~ 100 % efficiency No energy dispersion Beta- beam facility (not visible on the picture) Valve as rapid as possible CW input of RI
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ECR technique for RIB production
1 – « Slow ionization » Low density / long confinement / slow rising time / 1+ ionization / charge breeding / bunching / high efficiency 2 – « Rapid ionization » Higher density / shorter confinement / faster rising time High current / short pulsed development 3 – « Super bunching and ionization efficiency » With very high density plasma, is an « ECR-Duoplasmatron » possible ?
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Ion production of gaseous element To pump To beam
or metallic ion inside a very high temperature cavity To pump i.e. defined by the conductance of the extraction hole Dominant if ioni >> ext Atoms diffusion in molecular regime recycling 1+ To beam i.e. defined by the « ionic pumping » of the plasma Dominant if ioni ext plasma Ionization and diffusion in a magnetized plasma Target Ion source
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Ionization time and mean free path of ionization
vTi ne< ioni ve > ioni Fext 1-3 mm A+ Ti = 1/10 eV VTi = cm/s A° ne , Te Te = 50 eV VTe = cm/s ioni cm (from 0+ to Ar+) some cm < ioni ve > 10-7 cm3/s 7 cm at ne 1011 cm-3 2.45 GHz 10 µs ioni = tioni = 0.7 cm at ne 1012 cm-3 10 GHz 1 µs 0.07 cm at ne 1013 cm-3 28 GHz 0.1 µs 100 % efficiency and rapid ionization only if ioni < Fext so ne > 1013 e/cm-3
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1+ ionization of ions with ECR ion source
From Fredrik Wenander, Jacques Lettry, Nicolas Chritin, Ermanno Barbero, W. Pirkl, ISOLDE, CERN and G. Gaubert, P. Jardin, R. Leroy, et al., GANIL, Caen GANIL / ISOLDE MONOECRIS 1+ 2.45 GHz GANIL / Picogan 10 GHz the smallest ECRIS : L, F 3 cm release (50%) He ~ 20% 20 ms Ne ~ 35 % 30 ms Ar ~ 95% 40 ms Kr ~ 95% 40 ms ( Ar ) ~ 70%
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ECR Charge breeding for CW operation
Direct injection of atoms (gaseous ions only) simple confinement GANIL Nanogan /SPIRAL hNe1+ ® Ne6+ 10 % trelease tens of ms Direct injection of 1+ beams (gaseous or metallic ions) sophisticated confinement PHOENIX – ISN/SSI n+ Faraday Cup Double Einzel lens 1+ Faraday Cup 1+ spectrometer hNe1+ ® Ne6+ 10 % trelease tens of ms PHOENIX Booster n+ spectrometer Vertical pulsation Release : i .e. recycling + magnetic trapping 1+ source
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ECRIT charge breeding and bunching
From : T. Lamy et al., Institut des Sciences Nucléaires UJF-IN2P3-CNRS, Grenoble, France R.F. Power Rb1+ Injection Rbn+ Extracted tH.F. OFF ON t tinj Standard Values : t H.F. 300 ms to 2 s t inj 20 ms to t H.F. t 0 to 1.5 s h1+®15+ = 2.2 % (Rb ions) i.e. half of the CW 1 - Efficiency measurement of afterglow process 2 - Promizing results for ms and more, bunches of metallic ions 3 - Afterglow time difficult to control
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Very short confinement (some µs) Very poor gas efficiency
CERN duoplasmatron for H+ production the perfect time structure for the synchrotrons mA µs Very good time structure Very short confinement (some µs) Very poor gas efficiency
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PHOENIX 28 GHz : high current extraction (Xenon)
From : T. Thuillier et al., Institut des Sciences Nucléaires UJF-IN2P3-CNRS, Grenoble, France 35 mm Faraday Cup Xe17+ beam 3D field map of the 90° Bending magnet Xe18+ beam 10.4 emA (Xe emA) 3D field map of the solenoid 12.5 emA (IFC1) 3D source extraction field and magnetic fringe field of the source 15 emA (IHV)
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PHOENIX 28 GHz : high current extraction (Lead)
From : T. Thuillier et al., Institut des Sciences Nucléaires UJF-IN2P3-CNRS, Grenoble, France 10 emA total current (preliminary) 300 µs pulse Shorter and higher afterglow than with ECR GHz CERN 7 ( 10 ?)
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28 GHz experiment at grenoble ISN/SSI
From : T. Thuillier et al., Institut des Sciences Nucléaires UJF-IN2P3-CNRS, Grenoble, France 1 – Proof of the high frequency / high density effect 2 – Emittance and efficiency to be measured 3 - Afterglow shorter but always difficult to control (0.3-1 ms) 28 GHz /10 KW PHOENIX 28 GHz The new (and stable) 28 GHz /10 KW ISN gyrotron from GYCOM Inc. (Nizhny Novgorod , Russia) 5 µs shutdown of the full power
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SMIS 37.5 GHz with optical coupling
for very high intensity pulsed current From : S.V. Golubev, D.A. Mansfeld, S.V. Razin, V.A. Skalyga, A.V. Vodopyanov, V.G. Zorin, Institute of Applied Physics, Russian Academy of Sciences, Nizhniy Novgorod, Russia, R. Geller, T. Lamy, P. Sortais, T. Thuillier Institut des Sciences Nucléaires UJF-IN2P3-CNRS, Grenoble, France Optical coupling of the UHF power : up to 100 KW / 1 ms each 20 s Very simple magnetic system
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SMIS 37.5 GHz very high current density production
From : S.V. Golubev, D.A. Mansfeld, S.V. Razin, V.A. Skalyga, A.V. Vodopyanov, V.G. Zorin, Institute of Applied Physics, Russian Academy of Sciences, Nizhniy Novgorod, Russia, R. Geller, T. Lamy, P. Sortais, T. Thuillier Institut des Sciences Nucléaires UJF-IN2P3-CNRS, Grenoble, France Rising time 100 µs 30 emA / F 3 mm total current mAe/cm2 1013 part. during 100 µs with Multi Charged Ions To be done : beam matching (100 KV duoplasmatron extractor) efficiency measurement with pulsed valve upgrade to 60 or 90 GHz with pulsed or SC coils possible
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60-90 GHz « ECR Duoplasmatron » for gaseous RIB
1 – To bunch the gas in short time ~ > 20 µs 2 – To ionize (>1+) with a time smaller than the effusion time ne 1014 e/cm 60 GHz ECR discharge + strong axial magnetic field during the discharge ( 2T) 3 – To deliver a beam with a repetition rate compatible with the lifetime of the ions
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60-90 GHz « ECR Duoplasmatron » for gaseous RIB
2.0 – 3.0 T pulsed coils or SC coils Very high density magnetized plasma ne ~ 1014 cm-3 Very small plasma chamber F ~ 20 mm / L ~ 5 cm Target Arbitrary distance if gas Rapid pulsed valve 1-3 mm 100 KV extraction 60-90 GHz / KW 10 –200 µs / = 6-3 mm optical axial coupling UHF window or « glass » chamber (?) 20 – 100 µs 20 – 200 mA 1012 to 1013 ions per bunch with high efficiency optical radial coupling (if gas only)
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PHOENIX 28 GHz : afterglow control with Lead
Pb 25+,24+,23+,22+ Pb 16+ Pb 14+ a.u. O4+ O3+ O2+ C+ N+ O+ UHF pulse 10 ms “pre – glow” bunch correlated with presure drop Ionic pumping during some hundreds of µs 0 ms
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Simplification of the injection system
New RFQ LINAC 3 PSB
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Rapid ionization of RIB : future prospects
1 – ECRIS can supply either efficiency or pulsed currents ECRIS must supply efficiency AND pulsed currents 2 – 28 GHz / 10 KW preliminary tests could be done at ISN 3 – Possible extension to RIB of condensable elements and upgrade of the other metallic ion stable beams (Pb) next step of PHOENIX development 4 – Never start an heavy ion project without a strong preliminary ion source development program !
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