24 January 2001J. Lettry1 ISOLDE Introduction –PSB-beam, Targets –Ion-sources Facility performance –Front-ends and robots –Target production –Safety –Physics shifts Target developments –Yields (p-Energy) –n-converter –Alkali suppression –Future developments

24 January 2001J. Lettry2 Introduction PSB-beam Targets Ion-sources Separators

RILIS laser beams Nb cavity Tantalum oven Transfer line Diffusion Ionisation Effusion Diffusion Nuclear reaction UC 2 pills UC 2 target Graphite sleeve Release of 25 Na UC  C

24 January 2001J. Lettry4 High energy protons on 238-uranium - the production cross sections are summed for all isotopes of an element - the total cross section are given for 0.6, 1 and 1.4 GeV protons. Fission Spallation Fragmentation

24 January 2001J. Lettry5 p + beam density on ISOLDE targets: 90% ppp / 4  *  h*  v

24 January 2001J. Lettry6 Elements & Ion Sources Elements & Ion Sources ECR Negative PLASMA LIS Surface

24 January 2001J. Lettry7 Efficiencies of ISOLDE ion-sources

ISOLDE RILIS High temp. Ta-cavity LIS-ion bunch time structure

24 January 2001J. Lettry9 Facility performance 5 years average: 1 Shift ~ 2.5E17 protons 8h PSB at 6x3E13 p/scy ~ 3.6E17 protons  =70% Target assembly HRS operational, Robot singularity caused by grip and forearm alignment

24 January 2001J. Lettry10 Safety issues Light internal contamination during observation on the HRS front end –Long term follow up described in the ISOLDE consolidation project (M.L.) –E. Kugler is the new ISOLDE GLIMOS. UC 2 -Pills fire –Follow up completed, –Pills production resumes next week. Break of a Ta-carburisation oven –Physics run delayed by 2 days. Storage of Chemicals –~10 man-weeks required to reorganize the storage. –PS-PP supervisors for EP-PS shared chemical labs. Hg Laboratory ( -fact) –Hasop study of the Hg pump for high magnetic field tests done, assembly started.

Electrostatic quadrupole triplet Vacuum vessel Target ISOLDEfrontend ISOLDE front end Ion source -60kV Grounded x-y-z movable extraction electrode Ion beam Turbo molecular pumps (2  1000 l/min)

24 January 2001J. Lettry12 Target developments 2000 Alkali suppression n-converter Yields (p-Energy) LIS for “low” IP elements, Ga Future developments

24 January 2001J. Lettry13 Standard Reversed E-field While Low IP elements are surface ionized in the Ta-target oven and feel the DC heating current E-field, high IP elements remains unaffected Ratio of the release curves under Standard and reversed polarity of the target container E0 ~ ratio of the front and rear extraction holes surfaces D eff =  /(1+  ) with  =  i /  o  exp{-(W-IP)/kT} Reduction of low IP isobars produced in the high temperature metallic cavity of the RILIS Release curves Alkalis Rare earth

In neutron induced fission, the spallation and fragmentation processes are absent. Therefore, isobaric contamination is reduced by ~ 2 orders of magnitude Towards pulsed high power U &Th targets delivering very n-rich fission products High energy protons (~1GeV) impacting on Ta- & W-rods (converters) generate an intense neutron flux. The yields of very n-rich isotopes obtained via neutron induced fission of Th or U are close to those of high energy protons. Further developments: Geometrical optimum and n-reflectors  ISOLDE target and ion-source unit W-converter Ion-source PSB protons p+ beam-scan The thermal shock of the proton’s dE/dx is on the “cold” converter. The ion-release time structure is kept UC 2 target UC 2 + W-converter HT-oven electrical connections

24 January 2001J. Lettry Cs (1GeV p + ) Yield unit : [ions / micro Coulomb of protons] Historical unit from SC time [ions / s  A protons] 1  C protons = 6.25x10 12 protons highest Yields of the order of few ions / 1000 protons Spallation Fission

24 January 2001J. Lettry16 RILIS application on “low” ionization potential elements On line Ga tests, despite old CVL tubes, IS efficiency increased by one order of magnitude. The deep spallation product suppression is visible. Elements with IP close to 6 eV were surface ionized, a substantial ionization efficiency increase of ~ 30 was obtained off line.

24 January 2001J. Lettry developments 1 + ECR for ISOLDE 2  Nb target Alkali suppression for Spectroscopy within the LIS cavity n-converter study New LIS elements: –Germanium –Antimony

Conclusion A hell of a job… We did it…Thank to your support