1. LASER, Joint EURONS-EURISOL Town Meeting, Helsinki, Sept. 17, 2007 LASer techniques for Exotic nuclei Research (LASER) Iain Moore (JYFL) on behalf of the LASER collaboration Iain Moore (JYFL) on behalf of the LASER collaboration Participating institutes:  IKS – K.U. Leuven, Belgium  IPN – Orsay, IN2P3, France  IP-Quantum, Mainz, Germany  JYFL, Finland  ISOLDE, CERN, Switzerland  IKP, Mainz, Germany  GSI – Darmstadt, Germany  University of Manchester, UK

2. LASER, Joint EURONS-EURISOL Town Meeting, Helsinki, Sept. 17, 2007 To develop tools and perform R&D for the resonance ionization laser ion sources for the production of extremely pure ground state and isomeric beams of exotic nuclei. In-source laser spectroscopy Accumulation, cooling, bunching and polarization of radioactive ion beams Increase of ionization efficiency Increase of ionization efficiency Energy (eV) 0 4 Resonant Laser Ionization More efficient use of ISOL beams New exotic (polarized, isomeric) RIB Optimization of RIB time structure Easy injection into ion traps Determination of radii, spins and moments using in-source spectroscopy Reduction of background in collinear spectroscopy More efficient use of ISOL beams New exotic (polarized, isomeric) RIB Optimization of RIB time structure Easy injection into ion traps Determination of radii, spins and moments using in-source spectroscopy Reduction of background in collinear spectroscopy - purity - emittance - time structure Increase of ion beam quality Objectives

3. LASER, Joint EURONS-EURISOL Town Meeting, Helsinki, Sept. 17, 2007 Description of work: Task T-J08-1: Development of a new laser system for RILIS (K. Wendt, Mainz) Task T-J08-2: New laser ionisation schemes and new beams (I. Moore, JYFL) Task T-J08-3: Prototype LIST system (W. Nörtershäuser, GSI) Task T-J08-4: Improve selectivity of RILIS: reduction of surface ionisation (V. Fedosseev, ISOLDE) Task T-J08-5: Implementation of electrical fields in the gas cell concept (S. Franchoo, IPNO) Task T-J08-6: Feasibility study to polarize exotic nuclei with lasers (G. Neyens, K.U.Leuven) Research program

4. LASER, Joint EURONS-EURISOL Town Meeting, Helsinki, Sept. 17, 2007 Task 1 – Development of new laser system for RILIS Participants: U-Mainz, JYFL, U-Manchester, K.U. Leuven, ISOLDE, IN2P3 IPO Orsay  Development of prototype solid state laser system + doubling/tripling/quadrupling  Installed at U- Mainz, JYFL, TRIUMF, ORNL (tested)  Recent successful demonstration of injection-locked Ti:Sapphire laser with spectroscopy on 27 Al  Intercomparison of dye ↔ Ti:Sa and high rep rate ↔ low rep rate suitable at JYFL T. Kessler et al., Hyp. Int. 171 (2006) 121

5. LASER, Joint EURONS-EURISOL Town Meeting, Helsinki, Sept. 17, 2007 Laser development highlights T. Kessler et al., to be submitted U-Mainz and JYFL JYFL ~5 GHz Ti:Sa seeded to 20 MHz!

6. LASER, Joint EURONS-EURISOL Town Meeting, Helsinki, Sept. 17, 2007 Ti:Sapphire lasers pumped by Nd:YAG (12 kHz) CW dye lasers Pulsed dye lasers, pumped by CVL (12 kHz) or by 50 Hz Nd:YAG Full spectral coverage at a range of repetition rates, linewidths and powers…. FURIOS at JYFL – a twin laser facility I.D. Moore, J. Phys. G 31 (2005) S1499 2007 – LARIS lab setting up at ISOLDE, CERN 2008 – off-line RILIS ion source to be built

7. LASER, Joint EURONS-EURISOL Town Meeting, Helsinki, Sept. 17, 2007 Ti:Sapphire laser ion source Fe, Ni, Cu, Zn,Sn, New ionization schemes: Al, Ca, Fe, Ni, Cu, Ga, Zn, Ge, Y, Tc, Pd, Sn, Gd, Yb, Th, Pu (on-line experiments)

8. LASER, Joint EURONS-EURISOL Town Meeting, Helsinki, Sept. 17, 2007 Task 2 – New laser ionization schemes and new beams Participants: GSI A Selective and Efficient Ionization Scheme for Lithium

9. LASER, Joint EURONS-EURISOL Town Meeting, Helsinki, Sept. 17, 2007 R. Sánchez et al., PRL 96, 033002 (2006) Nature Physics 2, 145 (2006) M. Puchalski et al., PRL 97, 133001 (2006) R. Sánchez et al., PRL 96, 033002 (2006) Nature Physics 2, 145 (2006) M. Puchalski et al., PRL 97, 133001 (2006) Measurement of the charge radius of the halo nucleus 11 Li F=2 → F=2 F=1 → F=1

10. LASER, Joint EURONS-EURISOL Town Meeting, Helsinki, Sept. 17, 2007 Laser ionization of polonium at the ISOLDE-RILIS Participants: K.U. Leuven, ISOLDE, IN2P3 IPO Orsay, U-Mainz Development of 2 new laser ionization schemes for Po – first time for laser ionization of polonium First test to study the saturation capability of the chosen schemes

11. LASER, Joint EURONS-EURISOL Town Meeting, Helsinki, Sept. 17, 2007 Based on the extracted yields experiments have been proposed and performed: IS452, in-source spectroscopy of Po. The RILIS yields of n-deficient polonium isotopes are compared to the 20 year old yields obtained from the hot plasma source MK5. Note the U density in the target was 5 times less in the earlier work. Test in November 2006

12. LASER, Joint EURONS-EURISOL Town Meeting, Helsinki, Sept. 17, 2007 Study of ground-state properties of n-def Po Spectroscopy performed on the second transition new down to 182 Pb (T 1/2 = 55 ms) Odd-even staggering in Hg H. De Witte et al., Phys. Rev. Lett. 98 (2007) 112502 in-source laser spectroscopy: , Q,  (down to 193) decay spectroscopy post-accelerated (isomeric beams) with REX-ISOLDE: Coulomb excitation, transfer reaction studies K.U. Leuven, Mainz, ISOLDE, IPNO-Orsay

13. LASER, Joint EURONS-EURISOL Town Meeting, Helsinki, Sept. 17, 2007 430 nm 395 nm 842 nm 0 cm -1 23265 cm -1 48572 cm -1 7.28 eV 60453 cm -1 10 14 atoms of 99 Tc (t ½ = 2.1×10 5 years) on Re filament (Mainz) 3-step laser ionization scheme using Nd:YAG pumped Ti:Sapphire lasers (JYFL) Off-line laser ionization of Tc – towards N = Z studies Participants: JYFL, Mainz, KU-Leuven T. Kessler et al., Hyp. Int. 171 (2006) 121

14. LASER, Joint EURONS-EURISOL Town Meeting, Helsinki, Sept. 17, 2007 Off-line laser ionization of Tc – 2 step at LISOL

15. LASER, Joint EURONS-EURISOL Town Meeting, Helsinki, Sept. 17, 2007 Task 3 – Prototype LIST system 1.Atomic Beam Source with Surface Ion Repeller – Gas cell 3. Mass Separator 4. Laser System Proton Beam Ion Repeller to Experiments Laser- Beams HV Platform typical ISOL Source Ion Beam Ti:Sa 1 Ti:Sa 2 Ti:Sa 3 Nd:YAG Laser System Mass Separator Gas filled RFQ Trap 2. Gas filled RFQ Trap Section for Bunching and Cooling Production of isobarically pure ion beams with optimum spatial and temporal ion pulse control using a gas-filled RFQ structure Participants: GSI, Mainz, JYFL, Manchester

16. LASER, Joint EURONS-EURISOL Town Meeting, Helsinki, Sept. 17, 2007 The gas-filled linear RFQ trap

17. LASER, Joint EURONS-EURISOL Town Meeting, Helsinki, Sept. 17, 2007 Pulsed and cooled beams from LIST Maximum loading capacity 4×10 6 ions/cooling cycle

18. LASER, Joint EURONS-EURISOL Town Meeting, Helsinki, Sept. 17, 2007 JYFL sextupole ion guide Light-ion induced fusion-evaporation Proton-induced fission of uranium First LIST ions seen in using bismuth and technetium, optimizing of gas jet (Laval nozzle) I.D. Moore et al., Hyp. Int. 171 (2006) 135 P. Karvonen, I.D. Moore et al., to be submitted

19. LASER, Joint EURONS-EURISOL Town Meeting, Helsinki, Sept. 17, 2007 Task 4 – Improve selectivity of RILIS: reduce surface ions Participants: ISOLDE, U-Mainz + Neutrals Surface ionization Laser ionization Traditional tube materials:  tungsten Ø = 4.5 eV  tantalumØ = 4.2 eV  molybdenumØ = 4.6 eV at T > 2000 °C Selectivity10-20x Efficiency 10 %

20. LASER, Joint EURONS-EURISOL Town Meeting, Helsinki, Sept. 17, 2007 Other materials T 1200 °C, Eff = 10%, Selectivity > 1000, Emittance 1 π mm mrad GdB 6 Ø = 1.5 eV, BaOSrOØ < 1.4 eV

21. LASER, Joint EURONS-EURISOL Town Meeting, Helsinki, Sept. 17, 2007 Task 5 – Implementation of electrical fields in gas cells Participants: JYFL, Manchester, K.U. Leuven, U-Mainz, IPN Orsay  A new ion guide has been modelled and tested for the production of a low energy ion beam of daughter products from alpha-emitting isotopes.  Work is about to start on a design with an rf carpet, combined with DC fields at JYFL.  K.U. Leuven have tested a new gas cell where the laser ionization zone is shielded from the primary beam and stopping region. B. Tordoff et al., NIM B 252 (2006) 347

22. LASER, Joint EURONS-EURISOL Town Meeting, Helsinki, Sept. 17, 2007 363.3nm pumping 40% transfer 1 pA of 89 Y continuous beam Task 6 – Feasibility study to polarize nuclei with lasers Optical manipulation in the RFQ cooler (JYFL, Manchester) P. Campbell, Hyp. Int. 171 (2006) 143

23. LASER, Joint EURONS-EURISOL Town Meeting, Helsinki, Sept. 17, 2007 98 Y 97 Y 89 Y 96 Y 16.7 mins 98 Y 5.17 hrs Natural metastable population Effect of optical pumping from the ground state Several cases of interest: Niobium Platinum Osmium Rhenium Iridium Tungsten etc On-line success with neutron-rich yttrium

24. LASER, Joint EURONS-EURISOL Town Meeting, Helsinki, Sept. 17, 2007 LASER summary  Almost all milestones are on track to be completed, some (task 6) have evolved far beyond what was originally expected.  Associate partners have been participating in workshops and in sharing information throughout the laser community (ORNL Oak Ridge, TRIUMF Canada, Gatchina Russia).  Workshops organised: 2005 (Leuven), 2006 (Poznan – as part of Application of Lasers in Atomic Nuclei Research conference), 2007 (Saariselka, joint workshop with LASER-TRAPSPEC)  In most of the tasks, several facilities participated in developments and experiments, sending students to gain experience. Radioactive Ion Beam facility selectivity, efficiency, time structure isomeric beams management of the radioactive inventory

25. LASER, Joint EURONS-EURISOL Town Meeting, Helsinki, Sept. 17, 2007 68 Cu 6 - (+1 + ) 6-6- 1+1+  68m,g Cu (2.86 MeV/u, 3 10 5 pps, 74% pure) @ 120 Sn (2.3 mg/cm 2 ) 120 Sn 2 + -0 + Energy (keV) 68 Cu 1 + 85 T 1/2 =7.84 ns 1+1+ (2 + ) (3 + ) 6- 6- 4-4- (3 - ) 610 722 (5 - ) 0 956 778 0.7 <T 1/2 < 4 ns 178 693 85 3.7 min 30 s 6-6- 1+1+ 3.7 min 30 s 722 0 Post-accelerated isomeric Cu beams @ ISOLDE ISOLDE IPN-Orsay K.U. Leuven