F. Roesch1, A.F. Novgorodov2, D.V. Filossofov2, K.P. Zhernosekov1, N.A. Lebedev2, G.-J. Beyer3 and the ISOLDE Collaboration

Isolation of lanthanide, titanium, hafnium and other radioisotopes from massive targets (Ta, W, etc.)

irradiated with 1 GeV protons

1Institute of Nuclear Chemistry, Johannes Gutenberg-Universität Mainz, Germany

2Joint Institute of Nuclear Research, DLNP, 141980 Dubna, Russia; 3ISOLDE Collaboration

- Availability of nca radiolanthanides for basic radiochemical and radiopharmaceutical research- Production of nca radiolanthanides - Separation of nca radiolanthanides

aim

define isotopes of interest

coordinate irradiation concepts at CERN(targets,size of targets, irradiation periods etc.)with radiochemical separation (Geneva and Mainz)

management of applacation of isolated radionuclides

programme

CERN-Genevaisotope production

Baselcocktail

JINR DubnaRadiolanthanide

expertise

Mainzisotope separation

Transport of irradiated Ta converters

networking

Ta converters

after irradiation

ISOLDE targetsequipped with UC pellets for radioisotope production and a Tantalum (Ta)-bar for converting the incoming proton beam (E=1.4 GeV) into spallation neutrons

bar length of 150 mm, Ø 10 mm, mass 195 g

received a total dose of 2.5·1018 protons of 1.4 GeV

to assess activity and contamination levels, target dismounted

bar deformed by the deposited heat and shockwaves of the proton beams

strong deformation leads to the expectation of considerable inhomogeneity in activation

Radiochemical separation I: Ta /*Ln

[ separate nca. radiolanthanides from 195 g Ta ]

- dissolution of tantalum target in HF(conc) + HNO3 solution- dissolution process: 2 days

- isolation of the nca radiolanthanide *LnF3 fraction: by adding fine-dispersed charcoal

- filtration of the charcoal / *Ln fraction

Radiochemical separation II: *Ln separation

[ separate nca. radiolanthanides from each other: baseline ]

- desorption of *Ln from charcoal using B(OH)3

- purification (cyclic) of the nca *Ln fraction:1. precipitation as hydroxides *Ln(OH)3

2. centrifugation3. dissolution in < 0.1 ml 1 M HCl4. + 5 ml H2O + NH3 etc.

- transfer to cation exchange chromatography (AG6 / -HIB)

Isotope T1/2 activity (MBq)

Ce-139 137.6 d 19.7

Pm-143 265 d 189Pm-144 363 d 4.7Pm-146 5.53 a 0.26

Sm-145 340 d 109

Eu-147 24.1 d 0.3Eu-148 54.5 d 9.7Eu-149 93.1 d 0.7

individual nca radiolanthanides available: Ce - Eu

Isotope T1/2 activity (MBq)

Gd-146 48.27 d 35Gd-151 124 d 187Gd-153 241.6 d 221

Tb-160 72.3 d 0.03

Dy-159 144.4 d 100

Tm-168 93.1 d 4

Yb-169 32.03 a 4

individual nca radiolanthanides available: Gd - Yb

Isotope T1/2 activity (MBq)

Lu-173 1.37 a 133Lu-174 3.31 a 6

individual nca radiolanthanides available: Lu

Isotope T1/2 activity (MBq)

Lu-173 1.37 a 133Lu-174 3.31 a 6

Lu-172 6 d 50

via a 172Hf / 172Lu radionuclide generator

individual nca radiolanthanides available: Lu

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