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Positron emitter 94m Tc / p-induced nuclear reaction / Thermochromatographic separation / Routine isotope production AbstractThe thermochromatographic behaviour of "carrier-free" technetium species TcO, (x probably 3) and HTc0 4 was studied in dry and moist air atmospheres. Temperatures of adsorption on quartz surfaces (TJ were measured to be 400±40°C and 300±30°C, respectively, for the two technetium species for 20 min experimental periods. Two alternative routes for fast and quantitative thermochromatographic separation of the short-lived positron emitting technetium isotope 94m Tc from highly enriched molybdenum targets ( 94 Mo0 3 ) were tested. The optimum conditions to separate 94m Tc within 25 min, with overall radiochemical yields of about 80-85% (non-decay-corrected 40-45%) and in high radiochemical purity of >99% as pertechnetate, were developed. The radionuclidic purity at EOB was >90%. The separation process included an almost complete recovery and cyclic use of the enriched target material.

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Arsenic-72 is a positron emitting isotope with promising properties for syntheses of

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The distribution coefficients of Zr, Hf, Nb, Ta, Mo, W, and Pa on cation and anion exchange resins from mixed HCl/HF solutions were determined in batch experiments by radiometric measurements. From solutions of 0.05 to 0.1 M HCl with 1.0 X10"' M HF a Separation of subgroup V and VI from subgroup IV Clements is possible on DOWEX 50X8. This system is proposed for the fast on-line Separation of the Clements 105 and 106. In column experiments with cation exchangers W can be separated from Mo. This opens the possibility to determine the chemical behaviour of element 106 in comparison to the lighter homologs. Differenccs in the Sorption behaviour of Ta, Nb and Pa on cation exchange resins from 0.1 M HCl/2.0 X10"" M HF Solution should allow a Statement as to which of these Clements, element 105 has the highest similarity.

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