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Laser Spectroscopy with the Leuven gas cell-based Laser Ion Source @ LISOL

Laser Spectroscopy with the Leuven gas cell-based Laser Ion Source @ LISOL. OUTLINE Production of exotic beams with RILIS @ LISOL In-Gas Cell Laser Spectroscopy Progress toward a full implementation of In-Jet Laser Spectroscopy. Rafael Ferrer. Workshop and Users meeting 2011.

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Laser Spectroscopy with the Leuven gas cell-based Laser Ion Source @ LISOL

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  1. Laser Spectroscopy with the Leuven gas cell-based Laser Ion Source @ LISOL • OUTLINE • Production of exotic beams with RILIS @ LISOL • In-Gas Cell Laser Spectroscopy • Progress toward a full implementation of In-Jet Laser Spectroscopy Rafael Ferrer Workshop and Users meeting 2011 5-7 December 2011, CERN

  2. ResonanceIonization Laser Ion Source: RILIS • SELECTIVE (element and isomer) & EFFICIENT • PRODUCTION OF RARE ISOTOPE BEAMS U. Koester et al., Nucl. Phys. A 701 (2002) 441c • Gas Cell - Allelementsavailable • - T1/2 cellevacuation time • Sensitivity< 1 ion/s (97Ag) • Resol. ~ 3 GHz (59Cu) (Pressure) • ProducedIon beams~15 elements • Hot Cavity - No refractoryelements - T1/2 elementdependent • Sensitivity 1 ion/s (182Pb) • Resol~ 4 GHz (59Cu) (Doppler) • Produced Ion beams~30 elements • IN-SOURCE ATOMIC SPECTROSCOPY G. D. Alkhazov et al., NIM B69 (1992) 517 V.N. Fedoseevet al.,NIM B266 (2008) 4378 Yu. Kudryavtsevet al.,NIM B267 (2009) 2908 R. Ferrer - ISOLDE WORKSHOP ’11 -

  3. LISOL Beamssince 1994 Stopping of 185 MeVstable Ni beam Characterizationof gas cell NIM B 187 (2002) 535; NIM B 226 (2004) 401 Heavy Ion-inducedfusion evaporationreactions: Rh,Ru,Ti,Sn,In,Ag,Ac EPJ A 21 (2004)243 Light Ion-inducedfusion evaporationreactions: Co,Ni,Mn,Cr,V,Cu PRC 59 (1999) 2416 PRL 103 (2009) 102501 PRC 81 (2010)014314 Sp.fissionof 252Cf: Rh,Ru,Mo,Pd NIM B 266 (2008) 4368 • Implementation of ‘Dual Chamber’ gas cell • improves ionization efficiency and selectivity Proton-inducedfission of 238U: Fe,Co,Ni,Cu  In-source laser spectroscopy at LISOL PRL 81 (1998) 03100, PRC 64 (2001) 054308 PRC 74 (2006) 054309, PRC 78 (2008) 041307(R) PRC 79 (2009) 044309, PRC 79 (2009) 044325 Yu. Kudryavtev et al., NIM B 267 (2009) 2908 R. Ferrer - ISOLDE WORKSHOP ’11 -

  4. Dual Chamber Gas Cell Ar/He from gas purifier Laser beams Longitudinal • Separation of stopping and laser ionization volumes improves: • Laser ionization efficiency for high cyclotron beam current • Ion selectivity 500 mbar Stopping chamber Ø 4 cm Beam from Cyclotron Production of 94Rh Laser Ionization chamber Selectivity: [Laser(on)/Laser(off)] Ion Collector OFF = 450 Ion Collector ON = 2200 Ionization chamber Ø 1 cm Ion collector Ion Collector Filament Exit hole Ø 0.5 – 1 mm In-gas-cell spectroscopy of neutron deficient Cu isotopes T. E. Cocolioset al., PRL 103, 102501 (2009) T. E. Cocolioset al., PRC 81, 014314 (2010) Laser beams Transverse SPIG Similar measurements near N=Z line around A=100 R. Ferrer - ISOLDE WORKSHOP ’11 -

  5. N=50 In-Gas-Cell Laser Spectroscopy of Ag 92Mo(14N – 130 MeV,2pxn)104−xAg 64,natZn(36Ar – 125 MeV,pxn)101−97Ag 99Ag 97Ag 101Ag Derived experimental proton g-factors Open circle calculated value assuming I=7/2+ U. Dinger et al., Nucl. Phys. A 503 (1989) 331 D. Vandeplassche et al., Hyperfine Interact. 22 (1985) 483 IainDarbyPhys. Lett. B (in preparation) R. Ferrer - ISOLDE WORKSHOP ’11 -

  6. Attempt at Laser Spectroscopy of Sn continuum Aut. state 92Mo(16O-100 MeV,2-3n)105,106Sn IP 59232.69 cm-1 λ2=454.9 nm 1P1 39257.1 cm-1 • Strong l-dependence of Snon pressure • No possibility for HFS measurements (FWHM~20GHz) λ1=254.7 nm 3P0 argon argon 120Sn 120Sn l1 l2 Shift = -4.0(0.3) MHz/mbar Broadening=32(4) MHz/mbar Shift = -150(10) MHz/mbar Broadening=210(25) MHz/mbar R. Ferrer - ISOLDE WORKSHOP ’11 -

  7. Broadband Spectroscopy on Ac 197Au(20Ne-145 MeV,4-5n)212,213Ac 212Ac Cross section 2.3mb for 212,213Ac 1ST Step 2nd Step Ref. Cell @LARISSA continuum Ref. Cell @LARISSA 46660.6 cm-1 I.P. 43398 cm-1 227Ac 227Ac FWHM= 81 GHz FWHM= 24 GHz 439.21nm 23898.86 cm-1 4P5/2 Counts on SEM (arb. u.) 418.312 nm g.s. 2D3/2 Ac Gas Cell @LISOL Gas Cell @LISOL FULL POWER FWHM= 86 GHz FULL POWER FWHM= 170 GHz 212Ac 212Ac POWER ATTEN. FWHM= 32 GHz Alpha counts in 300 s Wavenumbers - 23898.93 (cm-1) Wavenumbers – 46660.65 (cm-1) http://www.gsi.de/forschung/ap/projects/laser/survey.html R. Ferrer - ISOLDE WORKSHOP ’11 -

  8. In-Jet Laser Spectroscopy • Increase Resolution and Sensitivity • - Ionization in cold jet expanding out of the gas cell Demonstrated proof of principle @ LISOL T. Sonodaet al. NIM B267 (2009) 2918 Ionization in LIST mode K. Blaumet al., NIM B204 (2003) 331 natNi Ref. Cell FWHM= ~ 2 GHz 58Ni Gas cell Ar 500 mbar FWHM=6.5 GHz SPIG 58Ni - Low density and low temperature in jet reduce significantly Doppler and pressure broadening FWHM= ~ 2 GHz 43089.6 43089.2 43090.0 • Requirementstoobtain full benefits: Wavenumber [cm-1] - Improve time and spatialoverlap of laser beamswithatoms R. Ferrer - ISOLDE WORKSHOP ’11 -

  9. Improving Time Overlap • Test of a high pulse repetition rate laser system • (Uni-Mainz & GANIL) - Performance comparison between high repetition Ti:sa lasers and LISOL dye lasers - Comparable results for in-gas-cell ionization - A factor of 60 reduction between in-gas- cell and in-jet ionization for Ti:sa lasers (700 reduction for dye lasers) - HFS of stable 63Cu in the SPIG limited by laser bandwidth R. F., V. Sonnenscheinet al,NIM B in preparation R. Ferrer - ISOLDE WORKSHOP ’11 -

  10. Improving Spatial Overlap • Implementation of de Laval nozzle and bent RFQ • - SIMION simulations of new segmented RFQ ion guide : • Transmission vs. p, RF amp, DC gradient Extraction RFQ RFQ Prototype 90o-bent RFQ pumping barrier Acceleration region Gas Cell - Test de Laval nozzle and new RFQ @LISOL • Awarded ERC Advanced Grant: new lab in K.U. Leuven for Heavy Element Laser Ionization Spectroscopy (HELIOS) • Final measurements @ S3 (SPIRAL2): Leuven gas cell • will couple fragment separator with HRS M. Reponen et al., NIM A 635 (2011) 24 R. Ferrer - ISOLDE WORKSHOP ’11 -

  11. Single Mode Selection in Dye Laser by a Thick Etalon • Study of typical LISOL narrow-band pulse using FP interferometer - Radial profile of interference ring shows four oscillation modes - Separation between modes is 400 MHz  mode FWHM= 150MHz Laser bandwidth ~1.4 GHz (SHG) • Implementation of a thicker etalon (14 mm air spaced) allows selection of a single mode •  Elimination of mode competition R. Ferrer - ISOLDE WORKSHOP ’11 -

  12. Spectrum of the low energy HFS components of the 244 nm line in 63,65Cu Ref. Cell B A 63Cu 450 MHz 65Cu • Bandwidth of 450 MHz without minimizing power nor Doppler broadening R. Ferrer - ISOLDE WORKSHOP ’11 -

  13. Amplification of CW Single Mode Diode Laser in Pulsed Dye Amplifier Tunable cw Diode Laser (Toptica) Dye Amplifier SHG Amp. II Amp. I Towards Ref. Cell 327.49 nm 654.98 nm KDP Excimer XeCl Laser R. Ferrer - ISOLDE WORKSHOP ’11 -

  14. Spectrum of the high energy HFS components of the 327 nm line in 63,65Cu D C D+C Ref. Cell • New ionization scheme required to meet tuneability of diode laser 63,65Cu 150 MHz 63Cu 65Cu • Estimated 90 MHz Fourier-limited (5ns) laser bandwidth is affected by residual • Doppler broadening resulting in a signal linewidthof 150 MHz R. Ferrer - ISOLDE WORKSHOP ’11 -

  15. Acknowledgments LISOL team: R.F, L. Ghys, M. Huyse, Yu. Kudryavtsev, D. Pauwels, D. Radulov, L. Rens, P. Van den Bergh, C. Van Beveren, and P. Van Duppen LISOL Alumni:T. Cocolios, I.G. Darby, T. Sonoda Collaborators: University of Mainz A. Hakimi, T. Kron, S. Raeder, S. Richter, J. Rossnagel, K. Wendt GANIL-SPIRAL2 B. Bastin, S. Franchoo, N. Lecesne, B. Osmond, H. Savajols , J. C. Thomas JYFL University of Jyväskylä I. Moore, M. Reponen, V. Sonnenschein JINR-Dubna S. Zemlyanoy R. Ferrer - ISOLDE WORKSHOP ’11 -

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