Preparation of self-supporting nickel targets for 58Ni ... · PDF filePreparation of Self-supporting Nickel Targets for 58Ni, ... • coating system Balzers BA510 ... Preparation of

Preparation of SelfPreparation of Self--supporting Nickel Targets supporting Nickel Targets for for 5858Ni, Ni, 6060Ni and Ni and 6161NiNi

Bettina Lommel, Willi Hartmann, Annett Huebner, Birgit Kindler and Jutta Steiner

INTDS 2010 Bettina Lommel 2

Table of ContentsTable of Contents

• Introduction• Motivation• Self-supporting Nickel• Backing• Electron-beam Evaporation

• 58Ni• 60Ni

• Extracted Ion-beam Evaporation• 61Ni

• Dissolving the Backing• Results



Targetlaboratory @ GSITargetlaboratory @ GSI

At the Targetlaboratory at GSI we• prepare out of solid materials

– targets– stripper foils– TOF foils– degrader

• prepare for – people from GSI for an experiment at GSI– people from outside for an experiment at GSI– people from GSI for an outside experiment



• provide enriched material for the ion sources• convert material

– from oxide in compound for easier evaporation– from metal in compound for longer lifetime in the beam– from oxide in metal for application in the ion source– .– .– .

• contact person for questions concerning materials• analytics



We produce targets over a wide thickness range• 10 nm -- ~ µm by

– resistive heating– thermal evaporation– e-beam gun evaporation– DC magnetron sputtering– HF magnetron sputtering– extracted ion beam sputtering



• 0.5 µm -- ~ 1 mm– by cold rolling– between stainless steel sheets– from foil or molten down bead– in air– in argon glove box



• 1 mm – several cm– by parallel cutting– by lapping– by polishing


MotivationMotivation

• investigation of the distribution of the fusion-barrier height by heavy-ion collisions

• first measurements with 20Ne on 90Zr and 92Zr [1] indicate certain fusion barrier height structure which can be attributed to energy level density

• interesting for self-supporting targets• interesting for Ni, choosing the double magic nuclei 58Ni and

other isotopes

• well known thickness• well known homogeneity • increases the accuracy of the measurement

[1] E.Piasecki et al., Phys. Rev. C80 (2009)


SelfSelf--supporting Nickelsupporting Nickel

• request for self-supporting nickel from a collaboration between the ‘Nuclear Reaction’ group at GSI and the University of Warsaw

• request for 58Ni, 60Ni and 61Ni• thickness 80 µg/cm² - 100 µg/cm² wanted• opening of the target frame ø = 15 mm

• starting material:– 58Ni enriched 99.92 % bought from Chemotrade

• natural abundance: 68.08 %– 60Ni enriched 99.79 % bought from ornl

• natural abundance: 26.22 %– 61Ni enriched 92.92 % bought from ornl

• natural abundance: 1.14 %


BackingBacking

• copper foil• 8 µm - 10 µm from Goodfellow®

• purity 99.9 %• annealed between copper electrodes• ~ 500 °C – 600 °C• cleaning of the surface• stress reduction• softening


5858NiNi

• coating system Balzers BA510®

• electron-beam gun Leyboldt KA6®

– max. acceleration voltage: 12 kV– max. power: 6 kW

• online thickness measurement by quartz gauge• water-cooled copper crucible• distance crucible – backing: 150 mm• starting material > 150 mg• ~ 100 µg/cm² 90 sec• size of the backing 100 mm x 100 mm • target thickness ± 10 µg/cm²• yield ~ 15 %

[2] Judith C. Gursky and John A O’Rourke, Nuclear Instruments and Methods, 53, (1967), 357-358




6060NiNi

• box coater Edwards AUTO 306®

• electron beam gun EB3– max. acceleration voltage: 5 kV– max. power: 3 kW

• online thickness measurement by quartz gauge• water-cooled copper crucible• distance crucible – backing: 50 mm; • rotating backing• starting material > 50 mg• ~ 100 µg/cm² 180 sec• target homogeneity limited by weight measurement• weight measurement of foil + frame• thickness homogeneity < 5 %• yield ~ 45 %






6161NiNi

• extracted ion-beam sputtering with Gatan Precision Etching Coating System Model 682®

• sputter voltage 6 keV• online thickness measurement by quartz gauge• rate 0,4 Å / sec.• 61Nickel foil on sputter target holder• distance sputter target – backing: 40 mm• rotating backing• ~ 100 µg/cm² 3000 sec• target homogeneity limited by weight measurement• weight measurement of foil + frame• thickness homogeneity < 5 %• yield ~ 10 %








Dissolving the BackingDissolving the Backing

• dissolving the copper foil• in ammoniacal trichloroacetic acid• no gas formation!

Cu + 4NH4OH + 2CCl3COOH [Cu(NH3)4 · 2H2O](CCl3COO)2+4H2O

• 10 – 15 % trichloroacetic acid• adding of ammoniac until pH-value of 12• copper precipitates• solution gets ink blue

O2

copper ammoniac trichloroacetic acid copper tetraamine chloridic acetate

[3] G. T. J. Arnison, Nucl. Instr. Meth. 53 (1967)






ResultsResults

• 58Ni: 95, 100 and 115 µg/cm²• 60Ni: 70 and 95 µg/cm²• 61Ni: 90 and 105 µg/cm²

• thickness measurement by weighing• confirmed by alpha-measurement ~ ± 5µg/cm²

• for expensive nickel isotopes the electron-beam evaporation with small distances and rotating backing is the most efficient method

• comparison of the homogeneity should come from the experiment


AcknowledgementAcknowledgement

Photos by Gabi Otto and Karolin Back, GSI

Alpha-measurement by Agnieszka Trzcinska, Warsaw University

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Preparation of self-supporting nickel targets for 58Ni ... · PDF filePreparation of Self-supporting Nickel Targets for 58Ni, ... • coating system Balzers BA510 ... Preparation of