The ISOLDE yield database Measured secondary beams intensities at ISOLDE

Pierre Delahaye for the ISOLDE collaboration

EURISOL DS Task 11 kick-off meeting, GSI, Darmstadt 18/03/05

Different target-ion sources system

Surface ionization

Hot plasma RILISCold plasma

ISOL targets• Different target materials1. molten metals: Ge, Sn, La, Pb, Bi, U,... 2. solid metals: Ti, Zr, Nb, Mo, Ta, W, Th,...3. carbides: Al4C3, SiC, VC, ZrC, LaCx, ThCx, UCx,...4. oxides: MgO, Al2O3, CaO, TiOx, ZrO2, CeOx, ThO2,...5. others: graphite, borides, silicides, sulfides, zeolithes,...

• Target dimensions:target container: 20 cm long, 2 cm diametertarget thickness 2—200 g/cm2, 10—100% of bulk densitymicro-dimensions of foils, fibers or pressed powder: 1—30 m

U. Köster for the ISOLDE Collaboration, Radiochimica Acta 89 (2001) 749.

• More than 1100 isotopes and 300 isomers produced so far, for more than 70 different elements• Secondary yields depends on several parameters: effusion, diffusion times, surface adsorption properties…

The ISOLDE database

• Production mode: proton pulses (~3.1013 per pulse during 2 s, 1.4 GeV) from PSB on a target/ n converter

• All measured data since 1993 are stored as Excel sheets

• SC yields are typically “good-day-yields”• The new ISOLDE web database PSB

Yields is quite incomplete. Concentrated on “new” elements

The Web SC database

Neutron rich onlyNeutron deficient only

SC-Yields estimate

• Proton beam intensities and energy 0.6 GeV

• CW beam. Straightforward analysis: no time dependence as soon as the equilibrium state has been reached

• only best results taken into account. Performances can change with time and target-ion source setup.

The PSB yields database

Only the most interesting yields are on-line available! Some data 1) analyzed but not published 2) not yet analyzed

The PSB yields database

Real status, from Ulli Koester

PSB-Yields estimate

• Fit of the yield release curves for the isotopes of one element

• Different conditions: target matrix, T, ion source, ageing

• Some traps: decay filiations – the mother nuclides remains (partly) in the matrix

Cumulative/ independent cross section

A quite careful analysis is required

Release profile ISOLDE

80Rb release80Rb release

Release = Diffusion + Desorption + Effusion

Release time profile is measured to characterize the performance of a target and ion source unit.

t=0: production of radioisotopes by 2 s short proton pulse

logarithmic linear

Empiric release formula

F(t) = N · (1-exp(-t/trise)) · ( · exp(-t/tfast) + (1-) · exp(-t/tslow))

80Rb release 80Rb release

Empiric 4-parameter formula:

J. Lettry et al., Nucl. Instr. Meth. B126 (1997) 130.

Analytical release model

Analytical model difficult to extend to:

• more complicated target geometries

• effusion of ions influenced by electric fields

• pulsed driver beam: > 1 GW/cm2 during 2 s thermal cycling of target, radiation enhanced diffusion,...

J.R.J. Bennett et al., Nucl. Instr. Meth. B126 (1997) 117. Nucl. Instr. Meth. B204 (2003) 211.

Monte Carlo release models

Monte Carlo program adaptable to all target and ion source geometries including various physical processes, but:

• difficult to deduce diffusion and desorption data from direct fit

• complete on-line test is an expensive method to test new materials

C.J. Densham et al., Nucl. Instr. Meth. B126 (1997) 154.

B. Mustapha and J.A. Nolen, Nucl. Instr. Meth. B204 (2003) 286.

Mario Santana-Leitner, PhD, 2005 (http://www.ganil.fr/eurisol/ )

Release delays

The required data are measured by TARGISOL: http://www.targisol.csic.es

Schedule and Manpower

• Manpower situation: - 1 EURISOL staff position in May, June - partial time- Lukic Strahinja, Post Doc, GSI, in next summer- summer student July August 2005- Ulli Köster supervising/providing support

• Preliminary schedule:- Summer 2005: evaluated yields as .xls- End 2005: newly measured and evaluated yields (during 2005)

• Special thanks to Ulli for the support and information concerning this presentation

• Thank you for your attention