1. Status Report of the LISOL Laser Ion Source Yu.Kudryavtsev, T.Cocolios, M.Facina, J.Gentens, M.Huyse, O.Ivanov, D.Pauwels, M.Sawicka, P.Van den Bergh, P.Van Duppen, Instituut voor Kern- en Stralingsfysika, K.U. Leuven, Celestijnenlaan 200 D, B-3001 Leuven, Belgium. Yu.Kudryavtsev, SMI06, March 27-28, 20061/24

2. CYCLONE 30 CYCLONE 110 CYCLONE 44 LISOL LASERS Louvain-la-Neuve Radioactive Beam Facility LASER ION SOURCE Yu.Kudryavtsev, SMI06, March 27-28, 2006 2/24

3. LISOL laser ion source Energy (eV) 0 4 laser + + + separator primary beam SPIG gas cell Ar target 3-10mg/cm 2 40 kV Time profiles of laser-ionized stable Ni-58 from a filament ~1994 We need to provide: 1. Efficient laser ionization 2. Survival of laser-produced ions in a small volume around the exit hole Weak beam, 1nA, 1ms Strong beam, 1uA,20ms Yu.Kudryavtsev, SMI06, March 27-28, 20063/24

4. Yu.Kudryavtsev, SMI06, March 27-28, 2006 LISOL Laser Ion Source is used since 1994 in 1.Light ion-induced fusion evaporation reactions (Co,Ni,Mn) 2.Heavy ion-induced fusion evaporation reactions (Rh,Ru,Ti) 3.Proton-induced fission of U-238 (Ni,Co,Fe,Cu) 4.Stopping of 185 MeV Ni beam in a gas cell 5.Products from spontaneous fission Californium-252 (Rh,Ru,Mo,Pd) 4/24

5. Lay out of the gas cell and ion extraction filament Fusion cell Fission cell Yu.Kudryavtsev, SMI06, March 27-28, 20065/24 500mbar Ar 1e-5mbar 1e-2 mbar

6. Dye Laser 2 Dye Laser 1 SHG Synchron. Unit Telescope Laser Ion Source at the LISOL front end Reference Cell Energy meters 15 m 1 2 TOF SEM Laser System Excimer laser 1 LPX240, 200Hz, 15ns Excimer laser 2 LPX240, 200Hz, 15ns Tunable range 225 - 800 nm Yu.Kudryavtsev, SMI06, March 27-28, 2006 6/24 Atomic beam Autoionizing state Energy (eV) 0 4 I.P.

7. Yu.Kudryavtsev, SMI06, March 27-28, 2006 Laser System Yu.Kudryavtsev, SMI06, March 27-28, 2006 Excimer lasers Dye lasers SHG Reference cell towards LIS 7/24

8. Two-step laser ionization schemes at LISOL - found @ tested on-line - found @ tested off-line Yu.Kudryavtsev, SMI06, March 27-28, 2006 80% of all elements can be ionized by the LISOL laser system in two steps The aim – refractory elements (thin target and fast extracion) 8/24

9. Yu.Kudryavtsev, SMI06, March 27-28, 2006 Detection set-up 9/24 Z 29 28 27 26 Proton-induced fission of U-238 - Studied isotopes - Isotopes measured in 2005

10. Yu.Kudryavtsev, SMI06, March 27-28, 2006 Gamma spectroscopy of neutron-reach Fe isotopes In June 2006 – 192 hours of beam time (protons 30 MeV) 10/24

11. Yu.Kudryavtsev, SMI06, March 27-28, 2006 Isospin symmetry test 54 Fe( 3 He,3n) 54 Ni N=Z Accurate comparison of Gamow -Teller transitions for A=46, 50 and 54 in beta decay and in ( 3 He,t) reactions 11/24 180

12. Yu.Kudryavtsev, SMI06, March 27-28, 2006 I  937 =250(35), Pk/B = 2.3 922 keV: 411+511 keV Half-life fit: Beam ONBeam OFF T 1/2 = 109 (13) ms I  937 =177(16), Pk/B = 11.3 P = 12 at/  C P = 17 at/  C Production of proton-reach nickel-54 isotope 3 He 2+ In April 2006 – 168 hours of beam time ( 3 He 45MeV) 54 Fe( 3 He,3n) 54 Ni Test experiment in 2005 12/24

13. Yu.Kudryavtsev, SMI06, March 27-28, 2006 Spontaneously fission of Californium-252 Independent Yields of Spontaneous Fission for Cf-252 105 MeV 85 MeV 112 Rh Life time – 2.645 y 252 Cf decays: 96.9% to  3.1% to fission fragments 13/24

14. Yu.Kudryavtsev, SMI06, March 27-28, 2006 Cf-252 gas cell Exit hole Gas in Water cooling Filament Laser beams Heating Length – 16 cm Inner diameter – 7 cm Exit hole diameter – 0.5 mm Evacuation time (Ar) – 0 - 10 s 14/24

15. Yu.Kudryavtsev, SMI06, March 27-28, 2006 Gas cell for production of radioactive ions from spontaneously fission Cf-252 Californium - 252 source: Diameter – 3 mm Activity – 25 MBq, April 2004, (4  ) Transmission through degrader foil – 33% Fission fragments inside gas – 2 E5 at/s Plasma density – 1e8 ion-el pairs/cm 3 Recombination time – 0.1 s 500 mbar Ar Laser beams Cf-252 Movable holder Al foil, 6u + + + + + + α α α α α α α α α + + Rh SRIM calculation 15/24 1. Survival of elements with different chemical properties can be studied 2. Absolute efficiency can be measured 500 mbar Ar

16. Yu.Kudryavtsev, SMI06, March 27-28, 2006  -gated gamma spectrum of Rh-112 from Cf-252 source Laser enhancement for Rh-112 isotopes from Cf-252 source lasers - ON lasers - OFF 560 keV 252 Cf Ar- 500mbar 52 mm Yield of 112 Rh into gas – 2.6% -> 5000 at/s Laser ionized mass separated yield – 250 at/s Efficiency – 5 % Selectivity: – 160 16/24

17. Yu.Kudryavtsev, SMI06, March 27-28, 2006 Gamma spectroscopy using spontaneously fission Cf-252 source 114 Rh Lasers - ON Lasers - OFF Spectroscopy 113 Rh - 116 Rh Branching ratios, life-times 17/24 252 Cf Ar- 500mbar 52 mm

18. Yu.Kudryavtsev, SMI06, March 27-28, 2006 Yield of Cesium isotopes from Californium source 40% 500 mbar Ar SPIG transport eff. – 60% Mass separator eff. – 90% 74% of Cs atoms stay in a single charge state Ionization potential of Cesium - 3.9 eV Distance to the exit hole-32 mm 252 Cf Ar- 500mbar 32 mm 18/24

19. Yu.Kudryavtsev, SMI06, March 27-28, 2006 Survival of Cesium Ions in Argon Short-leaved isotope can be used to probe the evacuation time inside the gas cell 252 Cf Ar- 500mbar Distance 19/24

20. Yu.Kudryavtsev, SMI06, March 27-28, 2006 The problem to be solved: Ion source efficiency at high cyclotron beam current 20/24

21. Yu.Kudryavtsev, SMI06, March 27-28, 2006 laserslasers gas Laser ion source efficiency for heavy ion-induced fusion evaporation reaction Extraction efficiency as function of primary 58 Ni beam intensity 40 Ar + 58 Ni => 98 Pd* => Rh/Ru + xp yn 95 Rh Ni beam 40 Ar 21/24

22. Lasers -off gas 58 Ni beam Recombination of laser-produced ions at high beam intensity Yu.Kudryavtsev, SMI06, March 27-28, 2006 Time profile of extracted 40 Ar ions High plasma density in the laser ionization region 22/24

23. 2.9E10ions/s LasersLasers gas 58 Ni beam Collector plate Collection of electrons after the cyclotron pulse Yu.Kudryavtsev, SMI06, March 27-28, 2006 23/24 Collection of electrons before laser ionization increases ion signal

24. Laser beams gas Target Stopping volume Ionization volume Cyclotron beam Separation of stopping and ionization volumes Yu.Kudryavtsev, SMI06, March 27-28, 2006 24/24