RILIS laser ion sources at ISOLDE/CERN. V. Fedosseev CERN, EN-STI-LP

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1 RILIS laser ion sources at ISOLDE/CERN V. Fedosseev CERN, EN-STI-LP

2 The proton beam and targets 50m PS Booster 0.6 GeV 1 GeV 1.4 GeV ppp Uranium carbide, metal compounds, foils or molten metal targets Thickness ~ g/cm 2 Temperature = K

3 The Ion Sources Resonance Surface Laser ionization ionization Electron impact ionization

4 RILIS at ISOLDE Facility RILIS

Selectivity = Surface Ionization Efficiency => depends on the ionization potentials of

5 Hot Cavity Laser Ion Source Efficiency: P P Ionisation Ionisation P Effusion Lasers located ~ 18 m away HOT CAVITY rep rep ion ion 2dv 3L 2 TARGET Laser Ionization Efficiency Selectivity = Surface Ionization Efficiency => depends on the ionization potentials of isobar atoms laser = 2% - 30% surface > 5% - alkalies = 0.1% -2% - In, Ga, Ba, lanthanides < 0.1% - others

6 RILIS ion beams Ion beams of 29 elements are produced at RILIS elements available at ISOLDE LIS 1 2 H ionization scheme tested He Li Be ionization scheme untested B C N O F Ne Na Mg Al Si P S Cl Ar K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn Fr Ra Ac Rf Ha Sg Ns Hs Mt Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr RILIS web page:

7 Wavelength tuning range Laser power, mw CVL-pumped dye laser tuning ranges Pyrr g/l P(G)=7W Pyrr g/l P(G)=7W Rhod 6G 0.5 g/l P(G)=7W Pyrr g/l P(G)=7W R6G+ Rhod B P(G)=8W Rhod B 1 g/l P(G)=9.2W Rhod B 1 g/l P(Y)=9W Rhod g/l P(Y)=8.5W DCM 0.6 g/l P(G)=12W Phenoxazone g/l P(G)=8W Phenoxazone g/l P(Y)=8.2W Rhod 700 fresh 0.5 g/l P(Y)=8.5W LDS g/l P(Y)=8W Styryl 8 (LDS751) 0.5 g/l P(G)=7W LDS g/l P(Y)=8W Styryl g/l (Meth) P(Y)=8W Styryl g/l (Meth) P(G)=11W Styryl g/l (DMSO) P(Y)=8.5W Oxazine g/l P(Y)=6.5W Oxazine g/l P(Y)=6.5W Nile Blue A (ISAN) 0.26g/l P(Y)=6.5W Rhod g/l Wavelength, Angs.

8 Ionization schemes with CVL pumped dye lasers 2 CVL 1 Al (5.99 ev) Ca (6.11 ev) Ga (6.00 ev) In (5.79 ev) Tl (6.11 ev) 3 CVL 2 DL 3 DL Li (5.39 ev) Na (5.14 ev) Sr (5.69 ev) Ce (5.54 ev) Nd (5.52 ev) Sm (5.64 ev) Eu (5.67 ev) Gd (6.15 ev) Tb (5.86 ev) Dy (5.94 ev) Ho (6.02 ev) 1 DL 1 DL 2 1 DL 2 Tm (6.18 ev) Yb (6.25 ev) Lu (5.43 ev) Actinides 3 CVL 2 DL 1 3 DL Mg (7.65 ev) Sc (6.56 ev) Mn (7.43 ev) Co (7.86 ev) Ni (7.64 ev) Cu (7.73 ev) Y (6.22 ev) Ag (7.58 ev) Tc (7.28 ev) Sn (7.34 ev) Pb (7.42 ev) Bi (7.29 ev) DL DL Cu (7.73 ev) Bi (7.29 ev) Be (9.32 ev) DL 2 DL DL Be (9.32 ev) Zn (9.39 ev) Cd (8.99 ev) Sb (8.61 ev) Po (8.42 ev) 3 DL DL DL Hg (10.39 ev) Au (9.23 ev)

9 Application of different ion sources at ISOLDE H Ionized with ISOLDE RILIS 1 Ionized with surface ion source Ionized with negative ion source Li Be B C N O F Ne Ionized with plasma ion source Na Mg Al Si P S Cl Ar K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn Fr Ra Ac Rf Ha Sg Ns Hs Mt He Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr

10 RILIS operation in SSL = 61% CVL = 39% Laser ON time in 2009: h - total 1992 h - on-line Hours In 2009 Nd:YAG lasers have been used for ALL 14 RILIS runs Year Be, Ga, Ag, Nd, Po, Mn, Mg, Po, Sn, Mg, Mn, Be, Zn, Ni

Upgrade of RILIS laser system Replacement of CVL by SSL Advantages: Better beam quality Stability

(Mn, Au) Service by manufacturer only CVL: SSL: 15 installed years of in service 2008 for at ISOLDE

harmonic (2) range: Fundamental () 530 Fundamental - 850 () 210-4252nd 390 nm harmonic - 850 nm(2)

11 Upgrade of RILIS laser system Replacement of CVL by SSL Advantages: Better beam quality Stability of operation Spectral coverage UV-NIR without gaps Complications: New ionization schemes are needed (Mn, Au) Service by manufacturer only CVL: SSL: 15 installed years of in service 2008 for at ISOLDE Wavelength tuning range: Fundamental () nm Wavelength tuning range: Wavelength tuning 2nd harmonic (2) range: Fundamental () 530 Fundamental () nd 390 nm harmonic nm(2) 2652nd nm (2) 3rd harmonic 3rd nm (3) (3) 2133rd harmonic (3) nm nm

New Nd:YAG lasers at ISOLDE RILIS Copper

Solid State Nd:YAG Lasers Two lasers are

Main green beam Residual green beam UV beam

green beam 532nm, 70-80 W, 8 ns Residual

12 New Nd:YAG lasers at ISOLDE RILIS Copper Vapor Lasers are replaced by Diode Pumped Solid State Nd:YAG Lasers Two lasers are available: one in use, second as a backup Main green beam Residual green beam UV beam Laser generates 3 beams at 10 khz: Main green beam 532nm, W, 8 ns Residual green beam 532 nm, W, 9 ns UV beam nm, W, 11 ns

13 SSL implementation in RILIS room CVL amplifiers CVL oscillator Dye lasers SSL power supply and chiller CVL power supply SSL laser systems

14 Alignment of laser beams in space Optical bench for controlling the beam focalization and space overlap Movable Al mirror Serves for both separators

15 HRS channel Laser beam control New Focus picomotor mounts GPS channel Optical path to HRS source = 23 m Optical path to GPS source = 18 m

16 Laser beam transport Prism box in HRS zone 2 o wedge plate 40x40 mm prism Flipping Al mirror GPS laser window 735 mr/h counts/s

17 SSL use: enhancements and current limitations elements available at ISOLDE LIS 1 2 H ionization scheme tested He Li Be ionization scheme untested B C N O F Ne Good example: Gallium Na Mg Al Si P S Cl Ar ( used in 2008 and 2009 for COLLAPS) K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe Two dye lasers were applied at 1 st step of Cs Ba La Hf Taexcitation W Re Os- >2x Ir improvement Pt Au Hg Tl Pb Bi Po At Rn More power could be delivered to HRS target at the 2 nd step of excitation Fr Ra Ac Rf Ha Sg Ns Hs Mt Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu CVL 2 2 SSL Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr More green power 1 DL nm dye DL pumping instead of 511 or 578 nm % are likely to benefit 46% from increased 46% final step power Most schemes are likely to Some schemes are no longer useable due to the 532 nm pump beam - lower final step efficiency or absorption cross section (Mn( Mn) - Need for a < 540 nm fundamental wavelength.

Fortuitous Auto-ionizing transition at CVL wavelength AIS search at LARIS Outcome of

18 A new RILIS scheme for manganese - LARIS result Replacement of the scheme which uses the CVL green beam. Fortuitous Auto-ionizing transition at CVL wavelength AIS search at LARIS Outcome of RIS study of Mn at LARIS: Many new auto-ionizing states found Various promising Nd:YAG based schemes tested New scheme applied at RILIS Efficiency > 8 %

Isomer selectivity with RILIS 287.9 nm 0.2 0.18 0.

4 nm 68 Cu ~13 GHz 68gCu 68mCu Applied also at REX/MINIBALL Worlds first

19 Isomer selectivity with RILIS nm m / g = 20 68gCu 68mCu nm 68 Cu ~13 GHz 68gCu 68mCu Applied also at REX/MINIBALL Worlds first post accelerated isomer purified beams 68 Cu intensity (a.u.) g / m = Transition frequency (cm -1 ) Separation of the 3 -decaying isomers in 70 Cu K. Blaum, PRL vol. 92 (2004) 11 (3 - ) (6 - ) (3 - ) (1 + ) (1 + )

20 In-source laser spectroscopy Ei=8.42 ev nm nm 6p 3 7s 3 S nm 511 nm CVL 6p 3 8p 6p 3 7p nm 6p 3 7s 5 S nm Techniques used to detect Po ions: detector with energy resolution detectors counter Faraday cap Annular Si Si 60 kev beam from ISOLDE Po 6s 2 6p 43 P 2 Ground state Spectral resolution is limited by Doppler width For transition at 843 nm D = 0.8 GHz

21 IS and HFS spectra of Polonium Even isotopes Odd isotopes (low spin)

22 RILIS after CVL-YAG transition More laser power -> higher ionization efficiency High stability of SSL power -> ion current stability much better Time from cold start of SSL to nominal operation ~ 30 min. No electromagnetic noise to experimental hall from RILIS New ionization scheme of Mn is developed CVLs can be removed from laser cabin SSL alignment and repair is possible only at EdgeWave UV power is limited by the optical resistance of harmonics crystals Efficiency of dye lasers is reduced due to shorter pump pulse Lifetime of dyes is reduced Operation of dye lasers and harmonics generators still requires continuous supervision by laser specialists

generation efficiency Improve UV pumping performance Allegro (made by Sirah GmbH)

23 Next steps Dye Laser Upgrade One narrow (1 GHz) and two broadband (15 GHz) lasers are ordered Improve beam quality, especially for UV beams Increase harmonic generation efficiency Improve UV pumping performance Allegro (made by Sirah GmbH) dye laser with amplifier and frequency doubling unit pumped by EdgeWave laser running at 10kHz

24 Next steps Nd:YAG pumped Ti:Sa system An additional independent fully solid state RILIS laser system Reduction of the reliance on laser dyes. Better coverage of the IR and blue spectral ranges Dual RILIS system could enable simultaneous RILIS setup and operation. Pump laser: 2 X commercial PI Nd:YAG, 532 nm, 60 W at 10 khz Tunable lasers: 3 single sided UMz Ti:Sapphire lasers - frequency doubling, tripling and quadrupling - computerized temporal and spectral control, 3 GHz, 30 ns - specs: nm, , nm Construction and purchasing of elements is started (Sebastian Rothe, PhD student in Mainz Uni and CERN) Space presently occupied by CVLs will be available for Ti:Sa system

25 Acknowledgments CERN, EN department Geneva, Switzerland Bruce Marsh Valentin Fedosseev Roberto Losito Sebastian Rothe Marica Sjödin K.U. Leuven, Instituut voor Kernen Stralingsfysica Leuven, Belgium Maxim Seliverstov Petersburg Nuclear Physics Institute, Gatchina, Russia Dima. Fedorov Yuri Volkov Pavel. Molkanov Anatoly Barzakh Victor Ivanov KTH Royal Institute of Technology Stockholm, Sweden Lars-Erik Berg Göran Tranströmer Thanks to Knut and Alice Wallenberg Foundation

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